Processing biomass to obtain hydroxylcarboxylic acids

ABSTRACT

Biomass (e.g., plant biomass, animal biomass, and municipal waste biomass) is processed to produce useful intermediates and products, such as hydroxy-carboxylic acids and hydroxy-carboxylic acid derivatives.

RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.14/786,388, filed Oct. 22, 2015, which is a National Stage entry ofInternational Application No. PCT/US2014/035467, filed Apr. 25, 2014,which claims priority to U.S. Provisional Application No. 61/816,664,filed Apr. 26, 2013, which are incorporated herein by reference in theirentirety.

BACKGROUND OF THE INVENTION

Many potential lignocellulosic feedstocks are available today, includingagricultural residues, woody biomass, municipal waste, oilseeds/cakesand seaweed, to name a few. At present, these materials are oftenunder-utilized, being used, for example, as animal feed, biocompostmaterials, burned in a co-generation facility or even landfilled.

Lignocellulosic biomass includes crystalline cellulose fibrils embeddedin a hemicellulose matrix, surrounded by lignin. This produces a compactmatrix that is difficult to access by enzymes and other chemical,biochemical and/or biological processes. Cellulosic biomass materials(e.g., biomass material from which the lignin has been removed) is moreaccessible to enzymes and other conversion processes, but even so,naturally-occurring cellulosic materials often have low yields (relativeto theoretical yields) when contacted with hydrolyzing enzymes.Lignocellulosic biomass is even more recalcitrant to enzyme attack.Furthermore, each type of lignocellulosic biomass has its own specificcomposition of cellulose, hemicellulose and lignin.

SUMMARY

Generally, this invention relates to methods and processes forconverting a material, such as a biomass feedstock, e.g., cellulosic,starchy or lignocellulosic materials, to useful products, for example,hydroxy-carboxylic acids (e.g., alpha, beta. gamma and deltahydroxy-carboxylic acids) and derivatives of hydroxy-carboxylic acids(e.g., esters). Such hydroxy-carboxylic acids can bepoly-hydroxy-carboxylic acids, e.g. di-, tri-, tetra-, penta-, hexa-hepta- and octa-hydroxy carboxylic acids. The poly-hydroxy-carboxylicacid can be substituted with other groups, e. g. alkyl groups. Thecarbon chain of the carboxylic acid can be straight chained, branched,cyclic, or alicyclic.

In one aspect the invention relates to a method for making a productincluding treating a reduced recalcitrance biomass (e.g.,lignocellulosic or cellulosic material) with one or more enzymes and/ororganisms to produce a hydroxy-carboxylic acid (e.g., an alpha, beta,gamma or delta hydroxy-carboxylic acid) and converting thehydroxy-carboxylic acid to the product. Optionally, the feedstock ispretreated with at least one method selected from irradiation (e.g.,with an electron beam), sonication, oxidation, pyrolysis and steamexplosion, for example, to reduce the recalcitrance of thelignocellulosic or cellulosic material. Some examples ofhydroxy-carboxylic acids that can be produced and then further convertedinclude glycolic acid, lactic acid, malic acid, citric acid, andtartaric acid (disubstituted), 3-hydroxybutyric acid (beta substituted),4-hydroxybutyric acid (gamma substituted), 3 hydroxyvaleric acid (betasubstituted), gluconic acid (tetra substituted at alpha, beta, gamma,and delta carbons with an additional hydroxy at the epsilon carbon).

In some implementation of the method, the hydroxy-carboxylic acid isconverted chemically, for example, by converting lactic acid to estersby treating with an alcohol and an acid catalyst. Other methods ofchemically converting that can be utilized include polymerization,isomerization, esterification, oxidation, reduction, disproportionationand combinations of these.

In some other implementation, the lignocellulosic or cellulosic materialis treated with one of more enzymes to release one or more sugars; forexample, to release glucose, xylose, sucrose, maltose, lactose, mannose,galactose, arabinose, fructose, dimers of these such as cellobiose,heterodimers of these such as sucrose, oligomers of these, and mixturesof these. Optionally, treating can further include (e.g., subsequentlyto releasing sugars) utilizing (e.g., by contacting with the sugarsand/or biomass) one or more organisms to produce the hydroxy-carboxylicacid. For example, the sugars can be fermented by a sugar fermentingorganism to the hydroxyl acid. Sugars that are released from the biomasscan be purified (e.g., prior to fermenting) by, for example, a methodselected from electrodialysis, distillation, centrifugation, filtration,cation exchange chromatography and combinations of these in any order.

In some implementation, converting comprises polymerizing the lacticacid to a polymer (e.g., polymerizing in a melt such as without an addedsolvent). For example, polymerizing methods can be selected from directcondensation of the lactic acid, azeotropic dehydrative condensation ofthe lactic acid, and dimerizing the lactic acid to lactide followed byring opening polymerization of the lactide. The polymerization can be ina melt (e.g., without a solvent and above the melting point of thepolymer) or can be in a solution (e.g., with an added solvent).

Optionally, when the polymerization method is direct condensation, thepolymerization can include utilizing coupling agents and/or chainextenders to increase the molecular weight of the polymer. For example,the coupling agents and/or chain extenders can include triphosgene,carbonyl diimidazole, dicyclohexylcarbodiimide, diisocyanate, acidchlorides, acid anhydrides, epoxides, thiirane, oxazoline, orthoester,and mixtures of these. Alternatively, the polymer can have a co monomerwhich is a polycarboxylic acid or polyols or a combination of these.

Optionally, polymerizations can be done utilizing catalysts and/orpromoters. For example, Lewis and Bronsted (protonic) acids can be used.Examples of the acids include H₃PO₄, H₂SO₄, methane sulfonic acid,p-toluene sulfonic acid, NAFION® NR 50 H+ form From DuPont, WilmingtonDel., Acids supported on polymers, metals, Mg, Al, Ti, Zn, Sn, metaloxides, TiO₂, ZnO, GeO₂, ZrO₂, SnO₂, Sb₂O₃, metal halides, ZnCl₂, SnCl₂,SnCl₄, Mn(AcO)₂, Fe₂(LA)₃, Co(AcO)₂, Ni(AcO)₂, Cu(OA)₂, Zn(LA)₂, Y(OA)₃,Al(i-PrO)₃,

Ti(BuO)₄, TiO(acac)₂, (Bu)₂SnO, tin octoate, solvates of any of theseand mixtures of these can be used.

The polymerizations or at least a portion of the polymerizations can bedone at a temperature between about 100 and about 200° C., such asbetween about 110 and about 170° C. or between about 120 and about 160°C. Optionally at least a portion of the polymerizations can be performedunder vacuum (e.g., between about 0.1 mm Hg to 300 mm Hg).

In the implementations wherein the polymerization method includesdimerizing the lactic acid to lactide followed by ring openingpolymerization of the lactide, the dimerization can include heating thelactic acid to between 100 and 200° C. under a vacuum of about 0.1 toabout 100 mmHg. Optionally, the dimerization (e.g., dimerizationreaction) can include utilizing a catalyst. Catalysts can, for example,include Sn octoate, Li carbonate, Zn diacetate dehydrate, Titetraisopropoxide, potassium carbonate, tin powder and mixtures ofthese. Optionally, a ring opening polymerization catalyst is utilized.For example, the ring opening polymerization catalyst can be chosen fromprotonic acids, HBr, HCl, triflic acid, Lewis acids, ZnCl₂, AlCl₃,anions, potassium benzoate, potassium phenoxide, potassium t-butoxide,and zinc stearate, metals, Tin, zinc, aluminum, antimony, bismuth,lanthanide and other heavy metals, Tin (II) oxide and tin (II) octoate(e.g., 2-ethylhexanoate), tetra phenyl tin, tin (II) and (IV)halogenides, tin (II) acetylacetonoate, distannoxanes (e.g.,hexabutyldistannoxane, R₃SnOSnR₃ where R groups are alkyl or arylgroups), Al(OiPr)₃, other functionalized aluminum alkoxides (e.g.,aluminum ethoxide, aluminum methoxide), ethyl zinc, lead (II) oxide,antimony octoate, bismuth octoate, rare earth catalysts, yttriumtris(methyl lactate), yttrium tris(2-N-N-dimethylamino ethoxide),samarium tris(2-N-N-dimethylamino ethoxide), yttrium tris(trimethylsilylmethyl), lanthanum tris(2,2,6,6-tetramethylheptanedionate), lanthanumtris(acetylacetonate), yttrium octoate, yttrium tris(acetylacetonate),yttrium tris(2,2,6,6-tetramethylheptanedionate), combinations of these(e.g., ethyl zinc/aluminum isopropoxide) and mixtures of these.

In the implementations wherein polymers are made from the lactic acid,the methods can further include blending the polymer with a secondpolymer. For example, a second polymer can include polyglycols,polyvinyl acetate, polyolefins, styrenic resins, polyacetals,poly(meth)acrylates, polycarbonate, polybutylene succinate, elastomers,polyurethanes, natural rubber, polybutadiene, neoprene, silicone, andcombinations of these.

In other implementations wherein polymers are made from the lactic acida co-monomer can be co-polymerized with the lactic acid or lactide Forexample, the co-monomer can include elastomeric units, lactones,glycolic acid, carbonates, morpholinediones, epoxides,1,4-benzodioxepin-2,5-(3H)-dione glycosalicylide,1,4-benzodioxepin-2,5-(3H, 3-methyl)-dione lactosalicylide, dibenzo-1,5dioxacin-6-12-dione disalicylide, morpholine-2,5-dione,1,4-dioxane-2,5-dione glycolide, oxepane-2-one ε-caprolactone,1,3-dioxane-2-one trimethylene carbonate, 2,2-dimethyltrimethylenecarbonate, 1,5-dioxepane-2-one, 1,4-dioxane-2-one p-dioxanone,gamma-butyrolactone, beta-butyrolactone,beta-methyl-delta-valerolactone, 1,4-dioxane-2,3-dione ethylene oxalate,3-[benzyloxycarbonyl methyl]-1,4-dioxane-2,5-dione, ethylene oxide,propylene oxide, 5,5′(oxepane-2-one),2,4,7,9-tetraoxa-spiro[5,5]undecane-3,8-dione, spiro-bis-dimethylenecarbonate and mixtures of these.

In any implementation wherein polymers are made, the polymers can becombined with fillers (e.g., by extrusion and/or compression molding).For example, some fillers that can be used include silicates, layeredsilicates, polymer and organically modified layered silicate, syntheticmica, carbon, carbon fibers, glass fibers, boric acid, talc,montmorillonite, clay, starch, corn starch, wheat starch, cellulosefibers, paper, rayon, non-woven fibers, wood flours, whiskers ofpotassium titanate, whiskers of aluminum borate, 4,4′-thiodiphenol,glycerol and mixtures of these.

In any implementation wherein polymers are made, the method can furtherinclude branching and/or cross linking the polymer. For example, thepolymers can be treated with a cross linking agent including5,5′-bis(oxepane-2-one)(bis-ε-caprolactone)), spiro-bis-dimethylenecarbonate, peroxides, dicumyl peroxide, benzoyl peroxide, unsaturatedalcohols, hydroxyethyl methacrylate, 2-butene-1,4-diol, unsaturatedanhydrides, maleic anhydride, saturated epoxides, glycidyl methacrylate,irradiation and combinations of these. Optionally, a molecule (e.g., apolymer) can be grafted to the polymer. For example, grafting can bedone treating the polymer with irradiation, peroxide, crossing agents,oxidants, heating or any method that can generate a cation, anion orradical on the polymer.

In any implementation wherein polymers are processed, processing caninclude injection molding, blow molding and thermoforming.

In any implementation wherein polymers are processed, the polymers canbe combined with a dye and/or a fragrance. For example, dyes that can beused include blue 3, blue 356, brown 1, orange 29, violet 26, violet 93,yellow 42, yellow 54, yellow 82 and combinations of these. Examples offragrances include wood, evergreen, redwood, peppermint, cherry,strawberry, peach, lime, spearmint, cinnamon, anise, basil, bergamot,black pepper, camphor, chamomile, citronella, eucalyptus, pine, fir,geranium, ginger, grapefruit, jasmine, juniper berry, lavender, lemon,mandarin, marjoram, musk, myrrh, orange, patchouli, rose, rosemary,sage, sandalwood, tea tree, thyme, wintergreen, ylang ylang, vanilla,new car or mixtures of these fragrances. Fragrances can be used in anyamount, for example, between about 0.005% by weight and about 20% byweight (e.g., between about 0.1% and about 5 wt. %, between about 0.25wt. % and about 2.5%).

In any implementation wherein polymers are processed, the polymer can beblended with a plasticizer. For example, plasticizers include triacetin,tributyl citrate, polyethylene glycol, GRINDSTED® SOFT-N-SAFE (fromDanisco, DuPont, Wilmington Del., diethyl bishydroxymethyl malonate) andmixtures of these.

In any of the implementations wherein polymers are made, the polymerscan be processed or further processed by shaping, molding, carving,extruding and/or assembling the polymer into the product.

In another aspect, the invention relates to products made by the methodsdiscussed above. For example, the products include a convertedhydroxy-carboxylic acid wherein the hydroxy-carboxylic acid is producedby the fermentation of biomass derived sugars (e.g., glycolic acid,D-lactic acid and/or L-lactic acid, D-malic acid, L-malic, citric acidand D-tartaric acid, L-tartaric acid and meso-tartaric acid). Thebiomass includes cellulosic and lignocellulosic materials and these canrelease sugars by acidic or enzymatic saccharification. In addition, thebiomass can be treated, e.g., by irradiation.

The products, for example, include polymers, including one or morehydroxyl acids in the polymer backbone and optionally non-hydroxycarboxylic acids in the polymer backbone. Optionally the polymers can becross-linked or graft co-polymers. Optionally the polymer can be,blended with a second polymer, blended with a plasticizer, blended withan elastomer, blended with a fragrance, blended with a dye, blended witha pigment, blended with a filler or blended with a combination of these.

In yet another embodiment, the invention relates to a system forpolymerization including a reaction vessel, a screw extruder and acondenser. The system also includes a recirculating fluid flow path froman outlet of the reaction vessel to an inlet of the screw extruder andfrom an outlet of the screw extruder to an inlet to the reaction vessel.In addition, the system includes a fluid flow path from a second outletof the reaction vessel to an inlet of the condenser. Optionally, thesystem further includes a vacuum pump in fluid connection with thesecond fluid flow path for producing a vacuum in the second fluid flowpath. Also optionally, the system can include a control valve that in afirst position provides a non-disrupted flow in the recirculating fluidflow path and in a second position provides a second fluid flow path. Insome implementations, the second fluid flow path is from the outlet ofthe reaction vessel to an inlet of a pelletizer. In otherimplementations, the second fluid flow path is from the outlet of thereaction vessel to the inlet of the extruder and from the outlet of theextruder to the inlet of a pelletizer.

Some of the products described herein, for example, lactic acid, can beproduced by chemical methods. However, fermentative methods can be muchmore efficient, providing high biomass conversion, selective conversionand high production rates. In particular, fermentative methods canproduce D or L isomers of hydroxy-carboxylic acids (e.g., lactic acid)at chiral purity of near 100% or mixtures of these isomers, whereas thechemical methods typically produce racemic mixtures of the D and Lisomers. When a hydroxy-carboxylic acid is listed without itsstereochemistry it is understood that D, L, meso, and/or mixtures areassumed.

The methods describe herein are also advantageous in that the startingmaterials (e.g., sugars) can be completely derived from biomass (e.g.,cellulosic and lignocellulosic materials). In addition, some of theproducts described herein such as polymers of hydroxy-carboxylic acids(e.g., poly lactic acid) are compostable, biodegradable and/orrecyclable. Therefore, the methods described herein can provide usefulmaterials and products from renewable sources (e.g., biomass) whereinthe products themselves can be re-utilized or simply safely returned tothe environment.

For example, some products that can be made by the methods, systems orequipment described herein include personal care items, tissues, towels,diapers, green packaging, compostable pots, consumer electronics, laptopcasings, mobile phone casings, appliances, food packaging, disposablepackaging, food containers, drink bottles, garbage bags, wastecompostable bags, mulch films, controlled release matrices, controlledrelease containers, containers for fertilizers, containers forpesticides, containers for herbicides, containers for nutrients,containers for pharmaceuticals, containers for flavoring agents,containers for foods, shopping bags, general purpose film, high heatfilm, heat seal layer, surface coating, disposable tableware, plates,cups, forks, knives, spoons, sporks, bowls, automotive parts, panels,fabrics, under hood covers, carpet fibers, clothing fibers, fibers forgarments, fibers for sportswear, fibers for footwear, surgical sutures,implants, scaffolding and drug delivery systems.

Other features and advantages of the invention will be apparent from thefollowing detailed description, and from the claims.

DESCRIPTION OF THE DRAWING

The foregoing will be apparent from the following more particulardescription of example embodiments of the invention, as illustrated inthe accompanying. The drawings are not necessarily to scale, emphasisinstead being placed upon illustrating embodiments of the presentinvention.

FIG. 1 is a flow diagram showing processes for manufacturing productsfrom a biomass feedstock

FIG. 2 is a schematic showing some biochemical pathways for thefermentation of sugars to lactic acid.

FIG. 3 is a schematic showing some of the possible lactic acid derivedproducts.

FIG. 4 is a schematic showing some possible chemical pathways forproducing poly lactic acid.

FIG. 5 is a schematic view of a reaction system for polymerizing lacticacid.

FIG. 6A is a top view of a first embodiment of a reciprocating scraper.FIG. 6B is a front cut-out view of the first embodiment of areciprocating scraper. FIG. 6C is a top view of a second embodiment of areciprocating scraper. FIG. 6D is a front cut-out view of the secondembodiment of a reciprocating scraper.

FIG. 7 is a plot of lactic acid production in a 1.2 L Bioreactor.

FIG. 8 is a plot of lactic acid production in a 20 L Bioreactor.

FIG. 9 is a plot of GPC data for poly lactic acid.

FIG. 10 shows the chemical structures of some exemplary hydroxyl acids.

DETAILED DESCRIPTION

Using the equipment, methods and systems described herein, cellulosicand lignocellulosic feedstock materials, for example, that can besourced from biomass (e.g., plant biomass, animal biomass, paper, andmunicipal waste biomass) and that are often readily available butdifficult to process, can be turned into useful products such as sugarsand hydroxy-carboxylic acids. Included are equipment, methods andsystems to chemically convert the primary products produced from thebiomass to secondary product such as polymers (e.g., poly lactic acid)and polymer derivatives (e.g., composites, elastomers and co-polymers).

Biomass is a complex feedstock. For example, lignocellulosic materialsinclude different combinations of cellulose, hemicellulose and lignin.Cellulose is a linear polymer of glucose. Hemicellulose is any ofseveral heteropolymers, such as xylan, glucuronoxylan, arabinoxylan andxyloglucan. The primary sugar monomer present (e.g., present in thelargest concentration) in hemicellulose is xylose, although othermonomers such as mannose, galactose, rhamnose, arabinose and glucose arepresent. Although all lignins show variation in their composition, theyhave been described as an amorphous dendritic network polymer of phenylpropene units. The amounts of cellulose, hemicellulose and lignin in aspecific biomass material depend on the source of the biomass material.For example, wood-derived biomass can be about 38-49% cellulose, 7-26%hemicellulose and 23-34% lignin depending on the type. Grasses typicallyare 33-38% cellulose, 24-32% hemicellulose and 17-22% lignin. Clearlylignocellulosic biomass constitutes a large class of substrates.

Enzymes and biomass-destroying organisms that break down biomass, suchas the cellulose, hemicellulose and/or the lignin portions of thebiomass as described above, contain or manufacture various cellulolyticenzymes (cellulases), ligninases, xylanases, hemicellulases or varioussmall molecule biomass-destroying metabolites. A cellulosic substrate isinitially hydrolyzed by endoglucanases at random locations producingoligomeric intermediates. These intermediates are then substrates forexo-splitting glucanases such as cellobiohydrolase to produce cellobiosefrom the ends of the cellulose polymer. Cellobiose is a water-soluble1,4-linked dimer of glucose. Finally, cellobiase cleaves cellobiose toyield glucose. In the case of hemicellulose, a xylanase (e.g.,hemicellulase) acts on this biopolymer and releases xylose as one of thepossible products.

FIG. 1 is a flow diagram showing processes for manufacturing is a flowdiagram showing processes for manufacturing hydroxy-carboxylic acidsfrom a feedstock (e.g., cellulosic or lignocellulosic materials). In aninitial step (110) the method includes optionally mechanically treatinga cellulosic and/or lignocellulosic feedstock, for example, tocomminute/size reduce the feedstock. Before and/or after this treatment,the feedstock can be treated with another physical treatment (112), forexample, irradiation, sonication, steam explosion, oxidation, pyrolysisor combinations of these, to reduce or further reduce its recalcitrance.A sugar solution e.g., including glucose and/or xylose, is formed bysaccharifying the feedstock (114). The saccharification can be, forexample, accomplished efficiently by the addition of one or moreenzymes, e.g., cellulases and/or xylanases (111) and/or one or moreacids. A product or several products can be derived from the sugarsolution, for example, by fermentation to a hydroxy-carboxylic acid(116). Following fermentation, the fermentation product (e.g., orproducts, or a subset of the fermentation products) can be purified orthey can be further processed, for example, polymerized and/or isolated(124). Optionally, the sugar solution is a mixture of sugars and theorganism selectively ferments only one of the sugars. The fermentationof only one of the sugars in a mixture can be advantageous as describedin International App. No. PCT/US2014/021813 filed Mar. 7, 2014, theentire disclosure of which is incorporated herein by reference. Ifdesired, the steps of measuring lignin content (118) and setting oradjusting process parameters based on this measurement (120) can beperformed at various stages of the process, for example, as described inU.S. Pat. No. 8,415,122, issued Apr. 9, 2013 the entire disclosure ofwhich is incorporated herein by reference. Optionally, enzymes (e.g., inaddition to cellulases and xylanases) can be added in step (114), forexample, a glucose isomerase can be used to isomerize glucose tofructose. Some relevant uses of isomerase are discussed in PCTApplication No. PCT/US12/71093, filed on Dec. 20, 2012, published as WO2013/096700 the entire disclosure of which is incorporated herein byreference.

In some embodiments the liquids after saccharification and/orfermentation can be treated to remove solids, for example, bycentrifugation, filtration, screening, or rotary vacuum filtration. Forexample, some methods and equipment that can be used during or aftersaccharification are disclosed in International App. No.PCT/US2013/048963 filed Jul. 1, 2013, and International App. No.PCT/US2014/021584, filed on Mar. 7, 2014, the entire disclosures ofwhich are incorporated herein by reference. In addition other separationtechniques can be used on the liquids, for example, to remove ions andde-colorize. For example, chromatography, simulated moving bedchromatograph and electrodialysis can be used to purify any of thesolutions and/or suspensions described herein. Some of these methods arediscussed in International App. No. PCT/US2014/021638, filed on Mar. 7,2014, and International App. No. PCT/US2014/021815, filed on Mar. 7,2014, the entire disclosures of which are incorporated herein byreference. Solids that are removed during the processing can be utilizedfor energy co-generation, for example, as discussed in InternationalApp. No. PCT/US2014/021634, filed on Mar. 7, 2014, the entire disclosureof which is herein incorporated by reference.

Optionally, the sugars released from biomass as described in FIG. 1, forexample, glucose, xylose, sucrose, maltose, lactose, mannose, galactose,arabinose, homodimers and heterodimers of these (e.g., cellobiose,sucrose), trimers, oligomers and mixtures of these, can be fermented tohydroxy-carboxylic acids such as alpha, beta or gamma hydroxyl acids(e.g., lactic acid). In some embodiments, the saccharification andfermentation are done simultaneously, for example, using thethermophilic organism such as Bacillus coagulans MXL-9 as described byS. L. Walton in J. Ind. Microbiol. Biotechnol. (2012) pg. 823-830.

Hydroxy-carboxylic acids that can be produced by the methods systems andequipment described herein include, for example, of alpha, beta, gamma,and delta hydroxy-carboxylic acids. FIG. 10 shows the chemicalstructures of some hydroxyl acids. That is, if there is only onehydroxyl group it can be at any of the alpha, beta, gamma or deltacarbon atoms in the carbon chain. The carbon chain may be a straightchain, branched or cyclic system. The hydroxy carboxylic acid may alsoinclude fatty acids of carbon chain lengths of 10 to 22 with the hydroxysubstituent at the alpha, beta, gamma, or delta carbon.

The hydroxy-carboxylic acids include those with multiple hydroxysubstituents, or in alternative description a poly hydroxy substitutedcarboxylic acid. Such hydroxy-carboxylic acids can bepoly-hydroxy-carboxylic acid, e.g. di-, tri-, tetra-, penta-,hexa-hepta- and octa-hydroxy substituted carboxylic acid. The carbonchain of the carboxylic acid may be straight chained, branched, cyclic,or alicyclic. Examples of this are tartaric acid and its isomers,dihydroxy-3-methylpentanoic acid, 3,4-dihydroxymandelic acid, gluconicacid, glucuronic acid and the like.

For example, the hydroxy-carboxylic acids include glycolic acid, lacticacid (e.g., D, L or mixtures of D and L), malic acid, citric acid,tartaric acid, carmine, cyclobutyrol, 3-dehydroquinic acid, diethyltartrate, 2,3-dihydroxy-3-methylpentanoic acid, 3,4-dihydroxymandelicacid, glyceric acid, homocitric acid, homoisocitric acid, beta-hydroxybeta-methylbutyric acid, 4-hydroxy-4-methylpentanoic acid,hydroxybutyric acid, 2-hydroxybutyric acid, beta-hydroxybutyric acid,gamma-hydroxybutyric acid, alpha-hydroxyglutaric acid,5-hydroxyindoleacetic acid, 3-hydroxyisobutyric acid, 3-hydroxypentanoicacid, 3-hydroxypropionic acid, hydroxypyruvic acid, gluconic acid,glucuronic acid, alpha, beta, gamma or delta-hydroxyvaleric acid;isocitric acid, isopropylmalic acid, kynurenic acid, mandelic acid,mevalonic acid, monatin, myriocin, pamoic acid, pantoic acid, prephenicacid, shikimic acid, tartronic acid, threonic acid, tropic acid,vanillylmandelic acid, xanthurenic acid and mixtures of these. For thosehydroxy-carboxylic acids listed all of the stereo isomers are includedin the list. For instance, tartaric acid includes, the D, L, and mesoisomers and mixtures thereof.

Preparation of Lactic Acid

Organisms can utilize a variety of metabolic pathways to convert thesugars to lactic acid, and some organisms selectively only can usespecific pathways. Some organisms are homofermentative while others areheterofermentative. For example, some pathways are shown in FIG. 2 andare described in Journal of Biotechnology 156 (2011) 286-301. Thepathway typically utilized by organisms fermenting glucose is theglycolytic pathway 2. Five carbon sugars, such as xylose, can utilizethe heterofermentative phosphoketolase (PK) pathway. The PK pathwayconverts two of the 5 carbons in xylose to acetic acid on the remaining3 to lactic acid (through pyruvate). Another possible pathway for fivecarbon sugars is the pentose phosphate (PP)/glycolytic pathway that onlyproduces lactic acid.

Several organisms can be utilized to ferment the biomass derived sugarsto lactic acid. The organisms can be, for example, lactic acid bacteriaand fungi. Some specific examples include Rhizopus arrhizus, Rhizopusoryzae, (e.g., NRRL-395, ATCC 52311, NRRL 395, CBS 147.22, CBS 128.08,CBS 539.80, CBS 328.47, CBS 127.08, CBS 321.35, CBS 396.95, CBS 112.07,CBS 127.08, CBS 264.28), Enterococcus faecalis (e.g. RKY1),Lactobacillus rhamnosus (e.g. ATCC 10863. ATCC 7469, CECT-288, NRRLB-445), Lactobacillus helveticus (e.g. ATCC 15009, R211), Lactobacillusbulgaricus (e.g. NRRL B-548, ATCC 8001, PTCC 1332), Lactobacillus casei(e.g. NRRL B-441), Lactobacillus plantarum (e.g. ATCC 21028, TISTR No.543, NCIMB 8826), Lactobacillus pentosus (e.g. ATCC 8041), Lactobacillusamylophilus (e.g. GV6), Lactobacillus delbrueckii (e.g. NCIMB 8130,TISTR No. 326, Uc-3, NRRL-B445, IFO 3202, ATCC 9649), Lactococcus lactisssp. lactis (e.g. IFO 12007), Lactobacillus paracasei No. 8,Lactobacillus amylovorus (ATCC 33620), Lactobacillus sp. (e.g. RKY2),Lactobacillus coryniformis ssp. torquens (e.g. ATCC 25600, B-4390),Rhizopus sp. (e.g. MK-96-4196), Enterococcus casseliflavus, Lactococcuslactis (TISTR No. 1401), Lactobacillus casei (TISTR No. 390),Lactobacillus thermophiles, Bacillus coagulans (e.g., MXL-9, 36D1,P4-102B), Enterococcus mundtii (e.g., QU 25), Lactobacillus delbrueckii,Acremonium cellulose, Lactobacillus bifermentans, Corynebacteriumglutamicum, L. acetotolerans, L. acidifarinae, L. acidipiscis, L.acidophilus, L. agilis, L. algidus, L. alimentarius, L. amylolyticus, L.amylophilus, L. amylotrophicus, L. amylovorus, L. animalis, L. antri, L.apodemi, L. aviarius, L. bifermentans, L. brevis (e.g., B-4527), L.buchneri, L. camelliae, L. casei, L. catenaformis, L. ceti, L.coleohominis, L. collinoides, L. composti, L. concavus, L. coryniformis,L. crispatus, L. crustorum, L. curvatus, L. delbrueckii subsp.Delbrieckii (e.g., NRRL B-763, ATCC 9649), L. delbrueckii subsp.bulgaricus, L. delbrueckii subsp. lactis (e.g., B-4525), L. dextrinicus,L. diolivorans, L. equi, L. equigenerosi, L. farraginis, L. farciminis,L. fermentum, L. fornicalis, L. fructivorans, L. frumenti, L.fuchuensis, L. gallinarum, L. gasseri, L. gastricus, L. ghanensis, L.graminis, L. hammesii, L. hamsteri, L. harbinensis, L. hayakitensis, L.helveticus, L. hilgardii, L. homohiochii, L. iners, L. ingluviei, L.intestinalis, L. jensenii, L. johnsonii, L. kalixensis, L.kefiranofaciens, L. kefiri, L. kimchii, L. kitasatonis, L. kunkeei, L.leichmannii, L. lindneri, L. malefermentans, L. mali, L. manihotivorans,L. mindensis, L. mucosae, L. murinus, L. nagelii, L. namurensis, L.nantensis, L. oligofermentans, L. oris, L. panis, L. pantheris, L.parabrevis, L. parabuchneri, L. paracollinoides, L. parafarraginis, L.parakefiri, L. paralimentarius, L. paraplantarum, L. pentosus, L.perolens, L. plantarum (e.g., ATCC 8014), L. pontis, L. psittaci, L.rennini, L. reuteri, L. rhamnosus, L. rimae, L. rogosae, L. rossiae, L.ruminis, L. saerimneri, L. sakei, L. salivarius, L. sanfranciscensis, L.satsumensis, L. secaliphilus, L. sharpeae, L. siliginis, L. spicheri, L.suebicus, L. thailandensis, L. ultunensis, L. vaccinostercus, L.vaginalis, L. versmoldensis, L. vini, L. vitulinus, L. zeae, L. zymae,and Pediococcus pentosaceus (ATCC 25745).

Alternatively, the microorganism used for converting sugars tohydroxy-carboxylic acids, including lactic acid, Lactobacillus casei,Lactobacillus rhamnosus, Lactobacillus delbrueckii subspeciesdelbrueckii, Lactobacillus plantarum, Lactobacillus coryniformissubspecies torquens, Lactobacillus pentosus, Lactobacillus brevis,Pediococcus pentosaceus, Rhizopus oryzae, Enterococcus faecalis,Lactobacillus helveticus, Lactobacillus bulgaricus, Lactobacillus casei,lactobacillus amylophilus and mixtures thereof.

Using the methods, equipment and systems described herein, either D or Lisomers of lactic acid at an optical purity of near 100% (e.g., at leastabout 80%, at least about 85%, at least about 90%, at least about 95%,at least about 99%) can be produced. Optionally, mixtures of the isomerscan be produced in any ratio, for example, from 0% optical purity of anyisomer up to 100% optical purity of any isomer. For example, the speciesLactobacillus delbrueckii (NRRL-B445) is reported to produce a mixtureof D and L isomers, Lactobacillus rhamnosus (CECT-28) is reported toproduce the L isomer while Lactobacillus delbrueckii (IF 3202) isreported to produce the D isomer (Wang et al. in Bioresource Technology,June, 2010). As a further example, organisms that predominantly producethe L(+)-isomer are L. amylophilus, L. bavaricus, L. casei, L.maltaromicus and L. salivarius, while L. delbrueckii, L. jensenii and L.acidophilus produce the D(−)-isomer or mixtures of both.

Genetically modified organisms can also be utilized. For example,genetically modified organisms (e.g., lactobacillus, Escherichia coli)that are modified to express either L-Lactate dehydrogenase or D-lactatedehydrogenase to produce more L-Lactic acid or D-Lactic acid,respectively. In addition, some yeasts and Escherichia coli have beengenetically modified to produce lactic acid from glucose and/or xylose.

Co-cultures of organisms, for example, chosen from organisms asdescribed herein, can be used in the fermentations of sugars tohydroxy-carboxylic acid in any combination. For example, two or morebacteria, yeasts and/or fungi can be combined with one or more sugars(e.g., glucose and/or xylose) where the organisms ferment the sugarstogether, selectively and/or sequentially. Optionally, one organism canbe added first and the fermentation proceed for a time, for example,until it stops fermenting one or more of the sugars, and then a secondorganism can be added to further ferment the same sugar or ferment adifferent sugar. Co-cultures can also be utilized, for example, to tunein a desirable racemic mixture of D and L lactic acid by combining aD-fermenting and L-fermenting organism in an appropriate ratio to formthe targeted racemic mixture.

In some embodiments, fermentations utilize Lactobacillus. For example,the fermentation of biomass derived glucose by Lactobacillus can be veryefficient (e.g., fast, selective and with high conversion). In otherembodiments the production of lactic acid uses filamentous fungi. Forexample, Rhizopus species can ferment glucose aerobically to lacticacid. In addition, some fungi (e.g. R. oryzae and R. arrhizus) produceamylases so that the direct fermentation of starches can accomplishedwithout adding external amylases. Finally some fungi (e.g., R. oryzae)can ferment xylose as well as glucose where most lactobacillus are notefficient in fermenting pentose sugars.

In some embodiments some additives (e.g., media components) can be addedduring the fermentation. For example, additives that can be utilizedinclude yeast extract, rice bran, wheat bran, corn steep liquor, blackstrap molasses, casein hydrolyzate, vegetable extracts, corn steepsolid, ram horn waste, peptides, peptone (e.g., bacto-peptone,polypeptone), pharmamedia, flower (e.g., wheat flour, soybean flour,cottonseed flour), malt extract, beef extract, tryptone, K₂HPO₄, KH₂PO₄,Na₂HPO₄, NaH₂PO₄, (NH₄)₂PO₄, NH₄OH, NH₄NO, urea ammonium citrate,nitrilotriacetic acid, MnSO₄.5H₂O, MgSO₄.7H₂O, CaCl₂. 2H₂O, FeSO₄.7H₂O,B-vitamins (e.g., thiamine, riboflavin, niacin, niacinamide, pantothenicacid, pyridoxine, pyridoxal, pyridoxamine, pyridoxine hydrochloride,biotin, folic acid), amino acids, sodium-L-glutamate, Na₂EDTA, sodiumacetate, ZnSO₄.7H₂O, ammonium molybdate tetrahydrate, CuCl₂, CoCl₂ andCaCO₃. Addition of protease can also be beneficial during thefermentation. Optionally, surfactants such as TWEEN™ 80 and antibioticssuch as chloramphenicol can also be beneficial. Additional carbonsources, for example, glucose, xylose and other sugars. Antifoamingcompounds such as Antifoam 204 can also be utilized.

In some embodiments the fermentation can take from about 8 hours toseveral days. For example, some batch fermentations can take from about1 to about 20 days (e.g., about 1-10 days, about 3-6 days, about 8 hoursto 48 hours, about 8 hours to 24 hours).

In some embodiments the temperature during the fermentation iscontrolled. For example, the temperature can be controlled between about20° C. and 50° C. (e.g., between about 25 and 40° C., between about 30and 40° C., between about 35 and 40° C.). In some cases, thermophilicorganisms are utilized that operate efficiently above about 50° C., forexample, between about 50° C. and 100° C. (e.g., between about 50-90°C., between about 50 to 80° C., between about 50 to 70° C.).

In some embodiments the pH is controlled, for example, by the additionof an acid or a base. The pH can be optionally controlled to be close toneutral (e.g., between about 4-8, between about 5-7, between about 5-6).Acids, for example, can be protic acids such as sulfuric, phosphoric,nitric, hydrochloride and acetic acids. Bases, for example, can includemetal hydroxides (e.g., sodium and potassium hydroxide), ammoniumhydroxide, and calcium carbonate. Phosphate and other buffers can alsobe utilized.

Fermentation methods include, for example, batch, fed batch, repeatedbatch or continuous reactors. Often batch methods can produce higherconcentrations of lactic acids, while continuous methods can lead tohigher productivities.

Fed batch methods can include adding media components and substrate(e.g., sugars from biomass) as they are depleted. Optionally, products,intermediates, side products and/or waste products, can be removed asthey are produced. In addition, solvent (e.g., water) can be added orremoved to maintain the optimal amount for the fermentation.

Options include cell-recycling. For example, using a hollow fibermembrane to separate cells from media components and products afterfermentation is complete. The cells can then be re-utilized in repeatedbatches. In other optional methods, the cells can be supported, forexample, as described in U.S. application Ser. No. 13/293,971, filed onNov. 10, 2011 and U.S. Pat. No. 8,377,668, issued Feb. 19, 2013, theentire disclosures of which are herein incorporated by reference.

The fermentation broth can be neutralized using calcium carbonate orcalcium hydroxide which can form calcium lactate. Calcium lactate issoluble in water (e.g., about 7.9 g/100 mL). The calcium lactate brothcan then be filtered to remove cells and other insoluble materials. Inaddition the broth can be treated with a decolorizing agent. Forexample, the broth can be filtered through carbon. The broth is thenconcentrated, e.g., by evaporation of the water optionally under vacuumand/or mild heating, and can be crystallized or precipitated.Acidification, for example, with sulfuric acid, releases the lactic acidback into solution which can be separated (e.g., filtered) from theinsoluble calcium salts, e.g., calcium sulfate. Addition of calciumcarbonate during the fermentation can also serve as a way to reduceproduct inhibition since the calcium lactate is not inhibitory or causesless product inhibition.

Optionally, reactive distillation can also be used to purify D-lacticacid and/or L-lactic acid. For example, methylation of D-lactic acidand/or L-lactic acid provides the methyl ester which can be distillatedto pure ester which can then be hydrolyzed to the acid and methanol thatcan be recycled. Esterification to other esters can also be used tofacilitate the separation. For example, reactions with alcohols to theethyl, propyl, butyl, hexyl, octyl or even esters with more than eightcarbons can be formed and then extracted in a solvent or distilled.

Other alternative D-lactic acid and/or L-lactic acid separationtechnologies include adsorption, for example, on activated carbon,polyvinylpyridine, zeolite molecular sieves and ion exchange resins suchas basic resins. Other methods include ultrafiltration andelectrodialysis.

Precipitation or crystallization of calcium lactate by the addition oforganic solvents is another method for purification. For example,alcohols (e.g., ethanol, propanol, butanol, hexanol), ketones (e.g.,acetone) can be utilized for this purpose.

Similar methods can be utilized for the preparation of otherhydroxy-carboxylic acids. For example, the fermentative methods andprocedures can be applicable for any of the hydroxy-carboxylic acidsdescribed herein.

Lactic Acid Uses

Lactic acid produced as described herein can be used, for example, inthe food industry as a preservative, acidulant and flavoring agent.Lactic acid can be used in a wide range of food applications such asbakery products, beverages, meat products, confectionery, dairyproducts, salads, dressings, ready meals. Lactic acid in food productsusually serves either as a pH regulator or as a preservative. It is canalso be used as a flavoring agent, for example, imparting a sour tasteto foods. Lactic acid can be used in meat, poultry and fish, forexample, in the form of sodium or potassium lactate to extend shelflife, control pathogenic bacteria (e.g., improving food safety), enhanceand protect meat flavor, improve water binding capacity and reducesodium. Lactic acid is also used as an acidity regulator in beveragessuch as soft drinks and fruit juices. Lactic acid is effective inpreventing the spoilage of olives, gherkins, pearl onions and othervegetables preserved in brine. Lactic acid can also be used as apreservative and/or flavoring additive in salads and dressings. Lacticacid is also used in formulating hard-boiled candy, fruit gums and otherconfectionery products. Lactic acid is used as an acidification agentfor many dairy products for example, yogurts and cheeses. Lactic acid isa natural sourdough acid, and therefore, it can be used for directacidification in the production of sourdough. Lactic acid is used toenhance a broad range of savory flavors, for example, in meat and dairyproducts.

Calcium lactate as produced by the methods described herein can also beadded to sugar-free foods to prevent tooth decay. For example, incombinations with chewing gum containing xylitol, it increases theremineralization of tooth enamel. Calcium lactate is also added tofresh-cut fruits such as cantaloupes to extend their shelf life.

The biomass derived lactic acid as described herein can be used inpharmaceutical applications, for example, for pH-regulation, metalsequestration, as a chiral intermediate and as a natural bodyconstituent in pharmaceutical products. Calcium lactate is commonly usedas an antacid and also as a calcium supplement. Other salts of lacticacid, for example, salts containing Mg, Zn and Fe, can also be used asmineral supplements and fortifying agents.

Lactic acid as produced by the methods described herein can also be usedin cleaning products. Lactic acid has descaling properties and is widelyapplied in household cleaning products. Also, lactic acid is used as anatural anti-bacterial agent in disinfecting products.

The lactic acid produced by the methods described herein can be used ina wide variety of industrial processes where acidity is required andwhere its properties offer specific benefits. Examples are themanufacture of leather and textile products and computer disks, as wellas car coatings.

The lactic acid as produced by the methods described herein can also beutilized as nutrient for animal feed. The lactic acid can have healthpromoting properties, thus enhancing the performance of farm animals.The lactic acid can be also used as an additive in food and/or drinkingwater both for animals and humans.

Products Derived from Lactic Acid

Lactic acid can be used as a platform chemical for many industriallyrelevant chemicals and products. For example, with reference to FIG. 2,lactic acid can be converted to, lactate esters such as ethyl lactate,acrylic acid, 1,2-propanediol, 2,3-pentanedione, acetaldehyde, propanoicacid and poly lactic acid.

1,2-propane diol (propylene glycol) can be used as a solvent andanti-freeze substitute for 1,2-propane diol. Propylene glycol is alsoused for de-icing solutions (e.g., airplane de-icing). Propylene glycolis approved for use as a food additive and can be used in food industryas a humectant, preservative, lubricant (e.g., for food processingequipment), solvent (e.g., for pharmaceutical preparations), plasticizer(e.g., for materials that come into contact with food).

Ethyl lactate has uses in pharmaceutical preparations, food additives,fragrances and as a fine chemical, consumer product (e.g., cosmetics)and industrial solvent.

Acetaldehyde is currently produced in a large scale, primarily frompetroleum sources. It is a synthon in a myriad of organic reactions toproduce, for example, ethyl acetate (an important solvent), perfumes,polyester resins and basic dyes. It also finds uses as a solvent (e.g.,in the rubber, tanning and paper industries), as a preservative (e.g.,fruit and meat), a flavoring agent and a denaturant for fuelcompositions.

2,3-pentanedione is useful as a solvent for cellulose acetate, paints,inks, lacquers. It is also a starting material for the synthesis ofdyes, pesticides and drugs. It also can be used as a constituent insynthetic flavoring agents.

(Meth)acrylic acid and its esters (e.g., methyl, butyl, ethyl,hydroxyethyl and 2-ethylhexyl esters) polymerize through their doublebond to form poly acrylates (e.g., polyacrylic acid). In addition,acrylic acid and its esters can copolymerize with other monomers e.g.,acrylamides, acrylonitriles, styrene, vinyl and butadiene) formingcopolymers which are used in manufacturing plastics, coatings,adhesives, elastomers, floor polishes and paints.

Propanoic acid can be used as a fungicide and bactericide, for treatmentof grains, hay, poultry litter, drinking water for animals as well asfor the treatment of areas used for storage of feed materials. It isalso a synthon for production of other chemicals, for example,herbicides and various esters.

Poly lactic acid is an important biodegradable/recyclable polymer thatwill be discussed in detail below.

Polymerization of Lactic Acid

Lactic acid prepared as described herein can undergo ester condensationto form dimers (e.g., linear and lactide), trimers, oligomers andpolymers. Polylactic acid (PLA) is therefore, a polyester of condensedlactic acid. PLA can be further processed (e.g., grafted, treated, orcopolymerized to form side chains including ionizable groups). Anothername for PLA is polylactide. Both isomers of PLA can form polymersand/or they can be copolymerized. The properties of the polymer dependstrongly on the amounts of the D and L lactic acid incorporated in thestructure, as will be discussed further on.

FIG. 4 shows methods for the production of PLA including: directcondensation combined with chain coupling; azeotropic dehydrativecoupling; and condensation followed by lactide formation and ringopening polymerization of the lactide.

A low molecular weight PLA can be produced catalyst free by the directself-condensation of lactic acid. This method produces low molecularweight polymers (e.g., about 1000 to 10,000 Mw, more typically about1000 to 5,000). The condensation produces water which can prevent theproduction of high molecular weight PLA since the ester condensationreaction is reversible. In addition, lactide can be produced bybackbiting from a chain end to form the lactide ring which reduces themolecular weight of the linear polymer. Therefore, the polycondensationsystem of PLA involves two equilibrium reactions; thedehydration/hydrolysis equilibrium for esterification/de-esterification;and the ring/chain equilibrium involving the depolymerization of PLAinto lactide or polymerization of the ring to linear polymer.

One method for production of high molecular weight PLA is by couplinglow Mw PLA, for example, made as described above, using chain couplingagents. For example, hydroxyl-terminated PLA can be synthesized by thecondensation of lactic acid in the presence of small amounts ofmultifunctional hydroxyl compounds such as, ethylene glycol, propyleneglycol, 1,3-propanediol, 1,2-cyclohexanediol, 2-butene-1,4-diol,glycerol, 1,4-butanediol, 1,6-hexanediol. Alternatively,carboxyl-terminated PLA can be achieved by the condensation of lacticacid in the presence of small amounts of multifunctional carboxylicacids such as maleic, succinic, adipic, itaconic and malonic acid. Otherchain extending agents can have heterofunctional groups that coupleeither on the carboxylic acid end group of the PLA or the hydroxyl endgroup, for example, 6-hydroxycapric acid, mandelic acid,4-hydroxybenzoic acid, 4-acetoxybenzoic acid.

Esterification promotion agents can also be combined with lactic acid toincrease the molecular weight of PLA. For example, ester promotionagents include phosgene, diphosgene, triphosgenedicyclohexylcarbodiimide and carbonyldiimidazole. Some potentiallyundesirable side products can be produced by this method addingpurification steps to the process. After final purification, the productcan be very clean, free of catalysts and low molecular weightimpurities.

The polymer molecular weights can also be increase by the addition ofchain extending agents such as isocyanates, acid chlorides, anhydrides,epoxides, thiirane and oxazoline and orthoester.

Azeotropic condensation polymerization is another method to obtain highmolecular weight polymer and does not require chain extenders orcoupling agents. A general procedure for this route consists of reducedpressure (between 0.1-300 mm Hg) refluxing of lactic acid for 1-10 hoursbetween 110° C.-160° C. to remove majority of the condensation water.Catalyst and/or solvents are added and heated further for 1-10 hoursbetween 110° C.-180° C. under 0.1-300 mm Hg. The polymer is thenisolated or dissolved (methylene chloride, chloroform) and precipitatedby the addition of a solvent (e.g., methyl ether, diethyl ether,methanol, ethanol, isopropanol, ethyl acetate, toluene) for furtherpurification. Solvents used during to polymerization, catalyst, reactiontime, temperature and level of impurities effect the rate ofpolymerization and hence the final molecular weight.

Additives, catalysts and promoters that can optionally be used includeLewis and Bronsted (protonic) acids such as H₃PO₄, H₂SO₄, methanesulfonic acid, p-toluene sulfonic acid, NAFION® NR 50 H+ form FromDuPont, Wilmington Del., metal catalysts, for example, include Mg, Al,Ti, Zn, Sn. Some metal oxides that can optionally catalyze the reactioninclude TiO₂, ZnO, GeO₂, ZrO₂, SnO, SnO₂, Sb₂O₃. Metal halides, forexample, that can be beneficial include ZnCl₂, SnCl₂, SnCl₄. Other metalcontaining catalysts that can optionally be used include Mn(AcO)₂,Fe₂(LA)₃, Co(AcO)₂, Ni(AcO)₂, Cu(OA)₂, Zn(LA)₂, Y(OA)₃, Al(i-PrO)₃,Ti(BuO)₄, TiO(acac)₂, (Bu)₂SnO. Combinations and mixtures of the abovecatalysts can also be used. For example, two or more catalysts can beadded at one time or sequentially as the polymerization progresses. Thecatalysts can also be removed, replenished and/or regenerated during thecourse of the polymerization are for repeated polymerizations. Optionalcombinations include protonic acids and one of the metal continuingcatalysts, for example, SnCl₂/p-toluenesulfonic acid.

The azeotropic condensation can be done partially or entirely using asolvent. For example, a high boiling and aprotic solvent such asdiphenyl ether, p-xylene, o-chlorotoluene, o-dichlorobenzene and/orisomers of these. The polymerization can also be done entirely orpartially using melt polycondensation. Melt polycondensations are doneabove the melting point of the polymers/oligomers without organicsolvents. For example, at the beginning of the polymerization when thereis a high concentration of low molecular weight species (e.g., lacticacid and oligomers) there can be less need for a solvent, while as themolecular weight of the polymers increases, the addition of a highboiling solvent can improve the reaction rates.

During the polymerization, for example, especially at the beginning ofthe polymerization when the concentration of lactic acid is high andwater is being formed at a high rate, the lactic acid/water azeotropicmixture can be condensed and made to pass through molecular sieves todehydrate the lactic acid which is then returned to the reaction vessel.

Copolymers can be produced by adding monomers other than lactic acidduring the azeotropic condensation reaction. For example, any of themultifunctional hydroxyl, carboxylic compounds or the heterofunctionalcompounds that can be used as coupling agents for low molecular weightPLA can also be used as co-monomers in the azeotropic condensationreaction.

Optionally, ring opening polymerization of lactide can provide PLA.Lactide can be produced by the depolymerization of low molecular weightPLA under reduced pressure. The depolymerization to form the lactidemonomers, for example, the D, L and meso forms, depends on thestereochemistry of the starting lactic acid and conditions of formation.Methods to form the lactide include condensing lactic acid, with orwithout catalysts at 110-180° C. and removing the water of condensationunder vacuum (1 mm Hg-100 mm Hg) to produce 1000-5000 molecular weightpolymer or prepolymer. The prepolymer can then be heated, for example,to temperatures of about 150-250° C. and at 0.1-100 mmHg to form anddistill off the crude lactic acid. The crude lactic acid can berecrystallized, for example, from a solution of dry toluene or ethylacetate.

Catalysts can be used for lactide formation. For example, catalysts thatcan be used include, tin oxide (SnO), Sn(II) octoate, Li carbonate, Zincdiacetate dehydrate, Ti tetraisopropoxide, potassium carbonate, tinpowder, combinations thereof and mixtures of these. Catalysts can beused in combination and/or sequentially.

The lactide monomer can be ring open polymerized (ROP) by solution,bulk, melt and suspension polymerization and is catalyzed by cationic,anionic, coordination or free radical polymerization. Some catalystsused, for example, include protonic acids, HBr, HCl, triflic acid, Lewisacids, ZnCl₂, AlCl₃, anions, potassium benzoate, potassium phenoxide,potassium t-butoxide, and zinc stearate, metals, Tin, zinc, aluminum,antimony, bismuth, lanthanide and other heavy metals, Tin (II) oxide andtin (II) octoate (e.g., 2-ethylhexanoate), tetraphenyl tin, tin (II) and(IV) halogenides, tin (II) acetylacetonoate, distannoxanes (e.g.,hexabutyldistannoxane, R₃SnOSnR₃ where R groups are alkyl or arylgroups), Al(OiPr)₃, other functionalized aluminum alkoxides (e.g.,aluminum ethoxide, aluminum methoxide), ethyl zinc, lead (II) oxide,antimony octoate, bismuth octoate, rare earth catalysts, yttriumtris(methyl lactate), yttrium tris(2-N-N-dimethylamino ethoxide),samarium tris(2-N-N-dimethylamino ethoxide), yttrium tris(trimethylsilylmethyl), lanthanum tris(2,2,6,6-tetramethylheptanedionate), lanthanumtris(acetylacetonate), yttrium octoate, yttrium tris(acetylacetonate),yttrium tris(2,2,6,6-tetramethylheptanedionate), combinations of these(e.g., ethyl zinc/aluminum isopropoxide) and mixtures of these.

In addition to homopolymer, copolymerization with other cyclic monomersand non-cyclic monomers such as glycolide, caprolactone, valerolactone,dioxypenone, trimethyl carbonate, 1,4-benzodioxepin-2,5-(3H)-dioneglycosalicylide, 1,4-benzodioxepin-2,5-(3H, 3-methyl)-dioneLactosalicylide, dibenzo-1,5 dioxacin-6-12-dione disalicylide,morpholine-2,5-dione, 1,4-dioxane-2,5-dione glycolide, oxepane-2-oneε-caprolactone, 1,3-dioxane-2-one trimethylene carconate,2,2-dimethyltrimethylene carbonate, 1,5-dioxepane-2-one,1,4-dioxane-2-one p-dioxanone, gamma-butyrolactone, beta-butyrolactone,beta-me-delta-valerolactone, 1,4-dioxane-2,3-dione ethylene oxalate,3-[benzyloxycarbonyl methyl]-1,4-dioxane-2,5-dione, ethylene oxide,propylene oxide, 5,5′(oxepane-2-one),2,4,7,9-tetraoxa-spiro[5,5]undecane-3,8-dione Spiro-bid-dimethylenecaronate can produce co-polymers. Copolymers can also be produced byadding monomers such as the multifunctional hydroxyl, carboxyliccompounds or the heterofunctional compounds that can be used as couplingagents for low molecular weight PLA.

FIG. 5 shows a schematic view of a reaction system for polymerizinglactic acid. The reaction system (510) includes a stainless steel jackedreaction tank (520), a vented screw extruder (528), a pelletizer (530),a heat exchanger (534) and a condensation tank (540). An outlet (521) ofthe reaction tank is connected to a tube (e.g., stainless steel) whichis connected to an inlet (545) to a heat exchanger. An outlet (546) tothe heat exchanger is connected to another tube (e.g., stainless steelor other corrosive resistant material) and is connected to an inlet(548) to the condensation tank (540). The tubes and connections from thereaction tank and condensation tank provide a fluid pathway (e.g., watervapor/air) between the two tanks. A vacuum can be applied to the fluidpathway between the tanks (520) and (540) by utilizing a vacuum pump(550) that is connected to port (549).

The reaction tank (520) includes an outlet (524) that can be connectedto a tube (e.g., stainless steel) that is connected to an inlet to ascrew extruder (560). An outlet to the extruder (562) is connected to atube which is connected optionally through a valve (560) to the reactiontank (520) through inlet (527). Optionally the outlet to the extruder(562) is connected through valve (560) to the pelletizer (530) throughinlet (532). Tubes and connections from the reaction tank and extruderprovide a circular fluid pathway (e.g., reactants and products) betweenthe reaction tank and extruder when the valve (560) is set inrecirculating position. The tubes and connections from the reaction tankto the pelletizer provide a fluid pathway between the reaction tank andpelletizer when the valve (560) is set in pelletizing position.

When in operation, the tank can be charged with lactic acid. The lacticacid is heated in the tank utilizing the stainless steel heating jacket(522). In addition, a vacuum is applied to the condensation tank (540)and therefore to the reaction tank (520) through the stainless steeltubing and connections using the vacuum pump (550). The heating of thelactic acid accelerates the condensation reactions (e.g., esterificationreactions) to form oligomers of PLA while the applied vacuum helpsvolatilize the water that is produced. Water vapor travels out of thereactants and out of the reaction tank (520) and towards the heatexchanger (534) as indicated by the arrow. The heat exchanger cools thewater vapor and the condensed water drops into the condensation tank(540) through the tubes and connections previously described. Multipleheat exchangers can be utilized. Since the hydroxy-carboxylic acids canbe corrosive the reactor equipment and other associated equipment may beclad or coated with corrosive resistant metals such as tantalum, alloyssuch as HASTELLOY™, a trademarked alloy from Haynes International, andthe like. It can also be coated with inert high temperature polymericcoatings such as TEFLON™ from DuPont, Wilmington Del. The corrosivity ofthe hydroxy-carboxylic acid system may not be surprising since the pKaof lactic acid is more than 0.8 less than acetic acid. Also, waterundoubtedly hydrates the acid and the acid end of the polymer. Whenthose waters of hydration are removed the acidity can be much higher,since it is not leveled by the waters of hydration.

In addition, during operation, extruder (528) can be engaged andoperated to draw the reactants (e.g., lactic acid, oligomers andpolymers) out of the tank. When the valve (560) is set in recirculatingposition the reactants are circulated back to the reaction tank in thedirection shown by the arrows. In addition to the extruder, the flow canbe controlled by valve (525), for example, the valve can be set toclosed for no flow, open for maximal flow or an intermediate positionfor lower or high flow rates (e.g., between about 0 and 100% open, e.g.,about 0%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90% or about 100%open).

The reaction can be continued with reactants following a circularpathway (e.g., with valve in recirculating position) until a desiredpolymerization is achieved. This circulating pathway provides mixing andshearing that can help the polymerization (e.g., increase molecularweight, control polydispersity, improve the kinetics of thepolymerization, improve temperature distribution and diffusion ofreacting species).The products (e.g. polymer) can then be directed tothe pelletizer by setting valve (560) to the pelletizing position. Thepelletizer then can produce pellets which can be collected. Pellets canbe of various shapes and sizes. For example, spherical or approximatelyspherical, hollow tube shaped, filled tube shape with, for example,approximate volumes, between about 1 mm³ to about 1 cm³. The pelletizercan also be replaced with other equipment, for example, extruders,mixers, reactors, and filament makers.

The extruder (528) can be a vented screw extruder so that water or othervolatile compounds can be removed from further processing. The extrudercan be a single screw extruder or a multiple screw extruder. Forexample, the extruder can be a twin screw extruder with co-rotating orcounter rotating screws. The screw extruder can also be a hollow flightextruder and can be heated or cooled. The screw extruder can be fittedwith ports to its interior. The ports can be utilized, for example, forthe addition of additives, addition of co-monomers, addition ofcross-linking agents, addition of catalysts, irradiation treatments andaddition of solvents. The ports can also be utilized for sampling (e.g.,to test the progress of the reaction or troubleshoot). In addition tosampling, the torque applied to the extruder can be used to monitor theprogress of the polymerization (e.g., as the viscosity increases). Aninline (e.g., a static mixer) mixer can also be disposed in the pathwayof the circulating reactants, for example, before or after the screwextruder, providing a tortuous path for the reactants which can improvethe mixing supplied to the reactants. The extruder can be sized, forexample, so that the material is recirculated, e.g., about 0.25-10 timesper hour (e.g., about 1-5 or 1-4 times per hour).

The position of the return port (527) allows the reactants to flow downthe side of the tank, increasing the surface area of the reactantsfacilitating the removal of water. The return port can include multiple(e.g. a plurality of ports) disposed at various positions in the tanks.For example, the plurality of return ports can be placedcircumferentially around the tank.

The tank can include a reciprocating scraper (529) which can help pushthe formed polymer/oligomers down the reaction tank, for example, duringor after completion of the reaction. Once the reciprocating scrapermoves down, the scraper can then be moved back up, for example, to aresting position. The scraper can be moved up and down the tank byengaging with and axel (640) that is attached to the hub (650). Inanother possible embodiment, the hub can be tapped for mechanicalcoupling to a screw, for example, wherein the axel is a screw-axel thatextends to the bottom of the tank. The screw-axel can then turn to drivethe scraper down or up.

A top view of one embodiment of a reciprocating scraper is shown in FIG.6A while a front cut out view is shown in FIG. 6B. The reciprocatingscraper includes pistons (620) attached to a hub (650) and scraping ends(630). The scraping end is in the form of a compression ring with a gap(660). The pistons apply pressure against the inside surfaces of thetank (615) through the scraping ends (630) while the scraper can bemoved down the tank as shown by the arrow in FIG. 6B. The gap (660)allows the expansion and contraction of the scraper. The scraper can bemade of any flexible material, for example, steel such as stainlesssteel. The gap is preferably as small as possible (e.g., less than about1″, less than about 0.1″, less than about 0.01″ or even less than about0.001″).

Another embodiment of a reciprocating scraper is shown in FIG. 6C andFIG. 6D. In this second embodiment the scraping ends include a lip-seal.The lip seal can be made of a flexible material, for example, rubber.The movement of the lip-seal as the scraper moves up and down acts as asqueegee against the inside of the reaction tank.

The tank (520) can be 100 gal in size, although larger and smaller sizescan be utilized (e.g., between about 20 to 10, 000 gal, e.g., at least50 gal, at least 200 gal, at least 500 gal, at least 1000 gal). Thetank, for example, can be shaped with a conical bottom or roundedbottom.

In addition to the inlets and outlets discussed, the tank can alsoinclude other openings, for example, to allow the addition of reagentsor for access to the interior of the tank for repairs.

During the reaction the temperature in the tank can be controlled frombetween about 100 and 180° C. The polymerization can preferably startedat about 100° C. and the temperature increased to about 160° C. overseveral hours (e.g., between 1 and 48 hours, 1 and 24 hours, 1 and 16hours, 1 and 8 hours). A vacuum can be applied between about 0.1 and 2mmHg). For example, at the beginning of the reaction about 0.1 mmHg andat the end of the reaction about 2 mmHg.

Water from the condenser tank (540) can be drained trough an opening(542) utilizing control valve (544).

The heat exchanger can be a fluid cooled heat exchanger. For example,cooled with water, air or oil. Several heat exchangers can be used, forexample, as needed to condense as much of the water as possible. Forexample, a second heat exchanger can be located between the vacuum pumpand the condensation tank (540).

The equipment and reactions described herein (e.g., FIG. 5) can also beused for polymerization of other monomers. In addition, the equipmentcan be utilized after or during the polymerizations for blending ofpolymers. For example, any of the hydroxyl acids described herein can bepolymerized by the methods, equipment and system described herein.

In addition to chemical method, lactic acid can be polymerized byLA-polymerizing enzymes and organisms. For example, ROP can be catalyzedby Candida antarctica lipase B, and hydrolases.

PLA Sterochemistry

Mechanical and thermal properties of pure PLA are largely determined bythe molecular weight and stereochemical composition of the backbone. Thestereochemical composition of the backbone can be controlled by thechoice and ratios of monomers; D-Lactic acid, L-Lactic acid oralternatively D-Lactide, L-Lactide or meso-Lactide. This stereochemicalcontrol allows the formation of random or block stereo copolymers. Themolecular weight of the polymers can be controlled, for example, asdiscussed above. The ability to control the stereochemical architectureallows, for example, precise control over the speed and degree ofcrystallinity, the mechanical properties, and the melting point andglass transition temperatures of the material.

The degree of crystallinity of PLA influences the hydrolytic stabilityof the polymer, and therefore, the biodegradability of the polymer. Forexample, highly crystalline PLA can take from months to years todegrade, while amorphous samples can be degraded in a few weeks to a fewmonths. This behavior is due in part to the impermeability of thecrystalline regions of PLA. Table 1 shows some of the thermal propertiesof some PLA of similarly treated samples. The percent crystallinity canbe calculated by using data form the table and applying the equation.

${\% \chi_{c}} = {\frac{\left( {{\Delta \; H_{m}} - {\Delta \; H_{c}}} \right)}{93} \cdot 100}$

Where ΔH_(m) is the melting enthalpy in J/g, ΔH_(c) is thecrystallization enthalpy in J/g and 93 is the crystallization enthalpyof a totally crystalline PLA sample in J/g.

As can be calculated from the data in the table, the crystallinity isdirectly proportional to the molecular weight of the pure L or pure Dstereo polymer. The DL stereoisomer (e.g., atactic polymer) isamorphous.

TABLE 1 Thermal properties of PLA Isomer M_(n) x M_(w)/ Tg T_(m) ΔHT_(c) ΔH type 10³ M_(n) (° C.) (° C.) (J/g) (° C.) (J/g) L 4.7 1.09 45.6157.8 55.5 98.3 47.8 DL 4.3 1.90 44.7 — — — — L 7.0 1.09 67.9 159.9 58.8108.3 48.3 DL 7.3 1.16 44.1 — — — — D 13.8 1.19 65.7 170.3 67.0 107.652.4 L 14.0 1.12 66.8 173.3 61.0 110.3 48.1 D 16.5 1.20 69.1 173.5 64.6109.0 51.6 L 16.8 1.32 58.6 173.4 61.4 105.0 38.1

Calculated crystallinities are in order top to bottom: 8.2%, 0%, 11.3%,0%, 15.7%, 13.8%, 14.0% and 25%.

The thermal treatment of samples, for example, rates of melting,recrystallization, and annealing history, can in part determine theamount of crystallization. Therefore, comparisons of the thermal,chemical and mechanical properties of PLS polymers should generally bemost meaningful for polymers with a similar thermal history.

The pure L-PLA or D-PLA has a higher tensile strength and low elongationand consequently has a higher modulus than DL-PLA. Values for L-PLA varygreatly depending on how the material is made e.g., tensile strengths of30 to almost 400 MPa, and tensile modulus between 1.7 to about 4.5 GPa.

PLA Copolymers, Crosslinking and Grafting

Variation of PLA by the formation of copolymers as discussed above alsohas a very large influence on the properties, for example, by disruptingand decreasing the crystallinity and modulating the glass transitiontemperatures. For example, polymers with increased flexibility, improvedhydrophilicity, better degradability, better biocompatibility, bettertensile strengths, improved elongations properties can be produced.

In many cases, the improvements are correlated with a decrease in theglass transition temperature. A few monomers can increase the glasstransition temperature of PLA. For example, lactones of salicylic acidscan have homopolymer glass transition temperatures between about 70 and110° C. and polymerize with lactide.

Morpholinediones, which are half alpha-hydroxy carboxylic acids and halfalpha-amino acids co-polymerize with lactide to give high molecularweight random co-polymers with lower glass transition temperatures(e.g., following the Flory-Fox equation). morpholinediones made up ofglycine and lactic acid (6-methyl-2,5-morpholinedione) whencopolymerized with lactide can give a polymer with glass transitiontemperatures of 109 and 71° C. for a 50 and 75 mol % lactic acidrespectively in the polymer. Morpholinediones have been synthesizedusing glycolic acid or lactic acid and most of the alpha amino acids(e.g., glycine, alanine, aspartic acid, lysine, cysteine, valine andleucine). In addition to lowering the glass transition temperature andimproving mechanical properties, the use of functional amino acids inthe synthesis of morpholinediones is an effective way of incorporatingfunctional pendant groups into the polymer.

As an example, copolymers of glycolide and lactide can be useful asbiocompatible surgical sutures due to increased flexibility andhydrophilicity. The higher melting point of 228° C. and Tg of 37° C. forpolyglycolic acid can produce a range of amorphous co-polymers withlower glass transition temperatures than PLA. Another copolymerizationexample is copolymerization with e-caprolactone which can yield toughpolymers with properties ranging from ridged plastics to elastomericrubbers and with tensile strengths ranging from 80 to 7000 psi, andelongations over 400%. Co-polymers of beta-methyl-gamma-valerolactonehave been reported to produce rubber-like properties. Co-polymers withpolyethers such as poly(ethylene oxide), poly(propylene oxide) andpoly(tetramethylene oxide) are biodegradable, biocompatible and flexiblepolymers.

Some additional useful monomers that can be copolymerized with lactideinclude 1,4-benzodioxepin-2,3(H)-dione glycosalicylide;1.3-benzodioxepin-2,5-(3H, 3-methyl)-dione Lactosalicylide;dibenzo-1,5-dioxacin-6,12-dione disalicylide; morpholine-2,5-dione,1,4-dioxane-2,5-dione, glycolide; oxepane-2-one trimethylene carbonate;2,2-dimethyltrimethylene carbonate; 1,5-dioxepane-2-one;1,4-dioxane-2-one p-dioxanone; gamma-butyrolactone; beta-butyrolactone;beta-methyl-delta-valerolactone; beta-methyl-gamma-valerolactone;1,4-dioxane-2,3-dione ethylene oxalate;3[(benzyloxycarbonyl)methyl]-1,4-dioxane-2,5-dione; ethylene oxide;propylene oxide, 5,5′-(oxepane-2-one) and 2,4,7,9-tetraoxa-spiro[5,5]undecane-3,8-dione Spiro-bis-dimethylene caronate.

PLA polymers and co-polymers can be modified by cross linking Crosslinking can affect the thermal and rheological properties withoutnecessarily deteriorating the mechanical properties. For example, 0.2mol % 5,5′-bis(oxepane-2-one)(bis-ε-caprolactone)) and 0.1-0.2 mol %spiro-bis-dimethylene carbonate cross linking Free radical hydrogenabstraction reactions and subsequent polymer radical recombination is aneffective way of inducing crosslinks into a polymer. Radicals can begenerated, for example, by high energy electron beam and otherirradiation (e.g., between about 0.01 Mrad and 15 Mrad, e.g. betweenabout 0.01-5 Mrad, between about 0.1-5 Mrad, between about 1-5 Mrad).For example, irradiation methods and equipment are described in detailbelow.

Alternatively or in addition, peroxides, such as organic peroxides areeffective radical producing and cross linking agents. For example,peroxides that can be used include hydrogen peroxide, dicumyl peroxide;benzoyl peroxide; 2,5-Dimethyl-2,5-di(tert-butylperoxy)hexane;tert-butylperoxy 2-ethylhexyl carbonate; tert-amylperoxy-2-ethylhexanoate; 1,1-di(tert-amylperoxy)cyclohexane; tert-amylperoxyneodecanoate; tert-amyl peroxybenzoate; tert-amylperoxy2-ethylhexyl carbonate; tert-amyl peroxyacetate;2,5-dimethyl-2,5-di(2-ethylhexanoylperoxy)hexane; tert-butylperoxy-2-ethylhexanoate; 1,1-di(tert-butylperoxy)cyclohexane; tert-butylperoxyneodecanoate; tert-butyl peroxyneoheptanoate; tert-butylperoxydiethylacetate;1,1-di(tert-butylperoxy)-3,3,5-trimethylcyclohexane;3,6,9-triethyl-3,6,9-trimethyl-1,4,7-triperoxonane;di(3,5,5-trimethylhexanoyl) peroxide; tert-butyl peroxyisobutyrate;tert-butyl peroxy-3,5,5-trimethylhexanoate; di-tert-butyl peroxide;tert-butylperoxy isopropyl carbonate; tert-butyl peroxybenzoate;2,2-di(tert-butylperoxy)butane; di(2-ethylhexyl) peroxydicarbonate;di(2-ethylhexyl) peroxydicarbonate; tert-butyl peroxyacetate; tert-butylcumyl peroxide; tert-amylhydroperoxide; 1,1,3,3-tetramethylbutylhydroperoxide, and mixtures of these. The effective amounts can vary,for example, depending on the peroxide, cross-linking reactionconditions and the desired properties (e.g., amount of cross linking).For example, cross-linking agents can be added from between about0.01-10 wt. % (e.g., about 0.1-10 wt. %, about 0.01-5wt. %, about 0.1-1wt. %, about 1-8 wt. %, about 4-6 wt. %). For example, peroxides such as5.25 wt. % dicumyl peroxide and 0.1% benzoyl peroxide are effectiveradical producing and cross linking agents for PLA and PLA derivatives.The peroxide cross-lining agents can be added to polymers as solids,liquids or solutions, for example, in water or organic solvents such asmineral spirits. In addition radical stabilizers can be utilized.

Cross linking can also be effectively accomplished by the incorporationof unsaturation in the polymer chain either by: initiation withunsaturated alcohols such as hydroxyethyl methacrylate or2-butene-1,4-diol; the post reaction with unsaturated anhydrides such asmaleic anhydride to transform the hydroxyl chain end; orcopolymerization with unsaturated epoxides such as glycidylmethacrylate.

In addition to cross linking, grafting of functional groups and polymersto a PLA polymer or co-polymer is an effective method of modifying thepolymer properties. For example, radicals can be formed as describedabove and a monomer, functionalizing polymer or small molecule. Forexample, irradiation or treatment with a peroxide and then quenchingwith a functional group containing an unsaturated bond can effectivelyfunctionalize the PLA backbone.

PLA Blending

PLA can be blended with other polymers as miscible or immisciblecompositions. For immiscible blends, the composition can be one with theminor component (e.g., bellow about 30 wt. %) as small (e.g., micron orsub-micron) domains in the major component. When one component is about30 to 70 wt. % the blend forms a co-continuous morphology (e.g.,lamellar, hexagon phases or amorphous continuous phases).

Blending can be accomplished by melt mixing above the glass transitiontemperature of the amorphous polymer components. Screw extruders (e.g.,single screw extruders, co-rotating twin screw extruders, counterrotating twin screw extruders) can be useful for this. For PLA polymersand co-polymers temperatures below about 200° C. can be used to avoidthermal degradation (e.g. below about 180° C.). Therefore, polymers thatrequire higher processing temperatures are not generally good candidatesfor blending with PLA.

Polyethylene oxide (PEO) and polypropylene oxide (PPO) can be blendedwith PLA. Lower molecular weight glycols (300-1000 Mw) are miscible withPLA while PPO becomes immiscible at higher molecular weight. Thesepolymers, especially PEO, can be used to increase the water transmissionand bio-degradation rate of PLA. They can also be used as polymericplasticizers to lower the modulus and increase flexibility of PLA. Highmolecular weight PEG (20,000) is miscible in PLA up to about 50%, butabove that level the PEG crystallizes, reducing the ductility of theblend.

Polyvinyl acetate (PVA) is miscible with PLA in all concentrations,where the blends show only one Tg is observed at all blend ratios, witha constant decrease to about 37° C. at 100% PVA. Low levels of PVA(5-10%) increase the tensile strength and % elongation of PLA whilesignificantly reducing the rate of weight loss during bio-degradation.

Blends of PLA and polyolefins (polypropylene and polyethylene) result inincompatible systems with poor physical properties due to the poorinterfacial compatibility and high interfacial energy. However, theinterfacial energy can be lowered, for example, by the addition of thirdcomponent compatibilizers, such as glycidyl methacrylate graftedpolyethylene. (irradiation would probably work) Polystyrene and highimpact polystyrene resins are also non-polar and blends with PLA aregenerally not very compatible

PLA and acetals can be blended making compositions with usefulproperties. For example, good, high transparency.

PLA is miscible with polymethyl methacrylate and many other acrylatesand copolymers of (meth)acrylates. Drawn films of PMMA/PLA blends aretransparent and have high elongation.

Polycarbonate can be combined with PLA up to about a 50 wt. %composition of Polycarbonate. The compositions have high heatresistance, flame resistance and toughness and have applications, forexample, in consumer electronics such as laptops. About 50 wt. %polycarbonate, the processing temperatures approach the degradationtemperature of PLA.

Acrylonitrile butadiene styrene (ABS) can be blended with PLA althoughthe polymers are not miscible. This combination is a less brittlematerial than PLA and provides a way to toughen PLA.

Poly(propylene carbonate) can be blended with PLA providing abiodegradable composite since both polymers are biodegradable.

PLA can also be blended with Poly(butylene succinate). Blends can impartthermal stability and impact strength to the PLA.

PEG, poly propylene glycol, poly(vinyl acetate), anhydrides (e.g.,maleic anhydride) and fatty acid esters have been added as plasticizersand/or compatibilizers.

Blending can also be accomplished with the application of irradiation,including irradiation and quenching. For example, irradiation orirradiation and quenching, as described herein applied to biomass can beapplied to the irradiation of PLA and PLA copolymers for any purpose,for example, before, after and/or during blending. This treatment canaid in the processing, for example, making the polymers more compatibleand/or making/breaking bonds within the polymer and/or blended additive(e.g., polymer, plasticizer). For example, between about 0.1 Mrad and150 Mrad followed by quenching of the radicals by the addition of fluidsor gases (e.g., oxygen, nitrous oxide, ammonia, liquids), usingpressure, heat, and/or the addition of radical scavengers. Quenching ofbiomass that has been irradiated is described in U.S. Pat. No. 8,083,906to Medoff, the entire disclosure of which is incorporated herein byreference, and the equipment and processes describe therein can beapplied to PLA and PLA derivatives. Irradiation and extruding orconveying of the PLA or PLA copolymers can also be utilized, forexample, as described for the treatment of biomass in U.S. applicationSer. No. 13/009,151 filed on May 2, 2011 the entire disclosure of whichis incorporated herein by reference.

PLA Composites

PLA polymers, co-polymers and blends can be combined with syntheticand/or natural materials. For example, PLA and any PLA derivative (e.g.,PLA copolymers, PLA blends, grated PLA, cross-linked PLA) can becombined with synthetic and natural fibers. For example, protein,starch, cellulose, plant fibers (e.g., abaca, leaf, skin, bark, kenaffibers), inorganic fillers, flax, talc, glass, mica, saponite and carbonfibers. This can provide a material with, for example, improvedmechanical properties (e.g., toughness, harness, strength) and improvedbarrier properties (e.g., lower permeability to water and/or gasses).

Nano composites can also be made by dispersing inorganic or organicnanoparticles into either a thermoplastic or thermoset polymer.Nanoparticles can be spherical, polyhedral, two dimensional nanofibersor disc-like nanoparticles. For example, colloidal or microcrystallinesilica, alumina or metal oxides (e.g., TiO₂); carbon nanotubes; clayplatelets.

Composites can be prepared similarly to polymer blends, for example,utilizing screw extrusion and/or injection molding. Irradiation asdescribed herein can also be applied to the composites, during, after orbefore their formation. For example, irradiation of the polymer andcombination with the synthetic and/or natural materials, or irradiationof the synthetic and/or natural materials and combination with thepolymer, or irradiation of both the polymer and synthetic and/or naturalmaterial and then combining, or irradiating the composite after it hasbeen combined, with or without further processing.

PLA with Plasticizers and Elastomers

In addition to the blends previously discussed, PLA and PLA derivativescan be combined with plasticizers.

For example, as described in J. Appl. Polym. Sci. 66: 1507-1513, 1997,PLA can be blended with monomeric and oligomeric plasticizers in orderto enhance its flexibility and thereby overcome its inherentbrittleness. Monomeric plasticizers, such as tributyl citrate, TbC, anddiethyl bishydroxymethyl malonate, DBM, can drastically decreased theT_(g) of PLA. Increasing the molecular weight of the plasticizers bysynthesizing oligoesters and oligoesteramides can result in blends withT_(g) depressions slightly smaller than with the monomeric plasticizers.The compatibility with PLA can be dependent on the molecular weight ofthe oligomers and on the presence of polar groups (e.g., amide groups,hydroxyl groups, ketones, esters) that can interact with the PLA chains.The materials can retain a high flexibility and morphological stabilityover long periods of time, for example, when formed into films.

Citrate esters can also be used as plasticizers with poly(lactic acid)(PLA). Films can be extruded, for example, using a single or twin-screwextruder with plasticizer contents (citrate esters or others describedherein) of between about 1 and 40 wt. % (e.g., about 5-30 wt. %, about5-25 wt. %, about 5-15 wt. %). Plasticizers such as citrate esters canbe effective in reducing the glass transition temperature and improvingthe elongation at break. The plasticizing efficiency can be higher forthe intermediate-molecular-weight plasticizers. The addition ofplasticizers can modulate the enzymatic degradation of PLA. For example,lower-molecular-weight citrates can increase the enzymatic degradationrate of PLA and the higher-molecular-weight citrates can decreased thedegradation rate as compared with that of unplasticized PLA.

Preparation of poly(lactic acid)/elastomer blends can also be preparedby melt blending technique, for example, as described in the Journal ofElastomers and Plastics, Jan. 3, 2013. PLA and biodegradable elastomercan be melt blended and molded in an injection molding machine. Themelting temperature can decrease as the amount of elastomer increases.Additionally, the presence of elastomer can modulate the crystallinityof PLA, for example, increasing the crystallinity by between about 1 and30% (e.g., between about 1 to 20%, between about 5 and 15%). The complexviscosity and storage modulus of PLA melt can decrease upon addition ofelastomer. The elongation at break can increase as the content ofelastomer increased while Young's modulus and tensile strength oftendecrease due to the addition of elastomer.

It has been observed that the cold crystallization temperature of theblends decreased as the weight fraction of elastomer increased as wellas the onset temperature of cold crystallization also shifted to lowertemperature. For example, as reported in the Journal of PolymerResearch, February 2012, 19:9818. In non-isothermal crystallizationexperiments, the crystallinity of PLA increased with a decrease in theheating and cooling rate. The melt crystallization of poly(lactic acid)appeared in the low cooling rate (1, 5 and 7.5° C./min). The presence ofsmall amounts of elastomer can also increase the crystallinity of poly(lactic acid). The DSC thermogram at ramp of 10° C./min showed themaximum crystallinity of poly(lactic acid) is 36.95% with 20 wt. %elastomer contents in blends. In isothermal crystallization, the coldcrystallization rate increased with increasing crystallizationtemperature in the blends. The Avrami analysis showed that the coldcrystallization was in two stages process and it was clearly seen at lowtemperature. The Avrami exponent (n) at first stage was varying from1.59 to 2 which described a one-dimensional crystallization growth withhomogeneous nucleation, whereas at second stage was varying from 2.09 to2.71 which described the transitional mechanism to three dimensionalcrystallization growth with heterogeneous nucleation mechanism. Theequilibrium melting point of poly(lactic acid) was also evaluated at176° C.

Some examples of elastomers that can be combined with PLA include:Elastomer NPEL001, Polyurethane elastomers (5-10%), Functionalizedpolyolefin elastomers, Blendex® (e.g., 415, 360, 338), PARALOID™ KM 334,BTA 753, EXL 3691A, 2314, Ecoflex® Supersoft Silicone Bionolle® 3001,Pelleethane® 2102-75A, Kraton® FG 1901X, Hytrel® 3078, and mixtures ofthese. Mixtures with any other elastomer, for example, as describedherein can also be used.

Some examples of plasticizers that can be combined with PLA include:Triacetin, glycerol triacetate, tributyl citrate, polyethylene glycol,GRINDSTED® SOFT-N-SAFE (acetic acid ester of monoglycerides) made fromfully hydrogenated castor oil and combinations of these. Mixtures withany other plasticizers, for example, as described herein can also beused.

The main characteristic of elastomer materials is the high elongationand flexibility or elasticity of these materials, against its breakingor cracking.

Depending on the distribution and degree of the chemical bonds of thepolymers, elastomeric materials can have properties or characteristicssimilar to thermosets or thermoplastics, so elastomeric materials can beclassified into: Thermoset Elastomers (e.g., do not melt when heated)and Thermoplastic Elastomers (e.g., melt when heated). Some propertiesof elastomer materials: Cannot melt, before melting they pass into agaseous state; swell in the presence of certain solvents; are generallyinsoluble; are flexible and elastic; lower creep resistance than thethermoplastic materials.

Examples of applications of elastomer materials described herein are:possible substitutes or replacements for natural rubber (e.g., materialused in the manufacture of gaskets, shoe heels); possible substitutes orreplacements for polyurethanes (e.g., for use in the textile industryfor the manufacture of elastic clothing, for use as foam, and for use inmaking wheels); possible substitutes or replacements for polybutadiene(e.g., elastomer material used on the wheels or tires of vehicles);possible substitutes or replacements for neoprene (e.g., used for themanufacture of wetsuits, wire insulation, industrial belts); possiblesubstitutes or replacements for silicone (e.g., pacifiers, medicalprostheses, lubricants). In addition, the materials described herein canbe used as substitutes for polyurethane and silicon adhesives.

Flavors, Fragrances and Colors

Any of the products and/or intermediates described herein, for example,hydroxyl acids, lactic acid, PLA, PLA derivatives (e.g., PLA copolymers,PLA composites, cross-linked PLA, grafted PLA, PLA blends or any otherPLA containing material prepared as described herein) can also becombined with flavors, fragrances colors and/or mixtures of these. Forexample, any one or more of (optionally along with flavors, fragrancesand/or colors) sugars, organic acids, fuels, polyols, such as sugaralcohols, biomass, fibers and composites, hydroxy-carboxylic acids,lactic acid, PLA, PLA derivatives can be combined with (e.g.,formulated, mixed or reacted) or used to make other products. Forexample, one or more such product can be used to make soaps, detergents,candies, drinks (e.g., cola, wine, beer, liquors such as gin or vodka,sports drinks, coffees, teas), pharmaceuticals, adhesives, sheets (e.g.,woven, none woven, filters, tissues) and/or composites (e.g., boards).For example, one or more such product can be combined with herbs,flowers, petals, spices, vitamins, potpourri, or candles. For example,the formulated, mixed or reacted combinations can haveflavors/fragrances of grapefruit, orange, apple, raspberry, banana,lettuce, celery, cinnamon, vanilla, peppermint, mint, onion, garlic,pepper, saffron, ginger, milk, wine, beer, tea, lean beef, fish, clams,olive oil, coconut fat, pork fat, butter fat, beef bouillon, legume,potatoes, marmalade, ham, coffee and cheeses.

Flavors, fragrances and colors can be added in any amount, such asbetween about 0.01 wt. % to about 30 wt. %, e.g., between about 0.05 toabout 10, between about 0.1 to about 5, or between about 0.25 wt. % toabout 2.5 wt. %. These can be formulated, mixed and/or reacted (e.g.,with any one of more product or intermediate described herein) by anymeans and in any order or sequence (e.g., agitated, mixed, emulsified,gelled, infused, heated, sonicated, and/or suspended). Fillers, binders,emulsifier, antioxidants can also be utilized, for example, proteingels, starches and silica.

The flavors, fragrances and colors can be natural and/or syntheticmaterials. These materials can be one or more of a compound, acomposition or mixtures of these (e.g., a formulated or naturalcomposition of several compounds). Optionally, the flavors, fragrances,antioxidants and colors can be derived biologically, for example, from afermentation process (e.g., fermentation of saccharified materials asdescribed herein). Alternatively, or additionally these flavors,fragrances and colors can be harvested from a whole organism (e.g.,plant, fungus, animal, bacteria or yeast) or a part of an organism. Theorganism can be collected and or extracted to provide color, flavors,fragrances and/or antioxidant by any means including utilizing themethods, systems and equipment described herein, hot water extraction,chemical extraction (e.g., solvent or reactive extraction includingacids and bases), mechanical extraction (e.g., pressing, comminuting,filtering), utilizing an enzyme, utilizing a bacteria such as to breakdown a starting material, and combinations of these methods. Thecompounds can be derived by a chemical reaction, for example, thecombination of a sugar (e.g., as produced as described herein) with anamino acid (Maillard reaction). The flavor, fragrance, antioxidantand/or color can be an intermediate and or product produced by themethods, equipment or systems described herein, for example, and esterand a lignin derived product.

Some examples of flavor, fragrances or colors are polyphenols.Polyphenols are pigments responsible for the red, purple and blue colorsof many fruits, vegetables, cereal grains, and flowers. Polyphenols alsocan have antioxidant properties and often have a bitter taste. Theantioxidant properties make these important preservatives. On class ofpolyphenols are the flavonoids, such as Anthrocyanins, flavonols,flavan-3-ols, flavones, flavanones and flavanonols. Other phenoliccompounds that can be used include phenolic acids and their esters, suchas chlorogenic acid and polymeric tannins.

Inorganic compounds, minerals or organic compounds can be used, forexample, titanium dioxide, cadmium yellow (e.g., CdS), cadmium orange(e.g., CdS with some Se), alizarin crimson (e.g., synthetic ornon-synthetic rose madder), ultramarine (e.g., synthetic ultramarine,natural ultramarine, synthetic ultramarine violet), cobalt blue, cobaltyellow, cobalt green, viridian (e.g., hydrated chromium(III)oxide),chalcophyllite, conichalcite, cornubite, cornwallite and liroconite.

Some flavors and fragrances that can be utilized include ACALEA TBHQ,ACET C-6, ALLYL AMYL GLYCOLATE, ALPHA TERPINEOL, AMBRETTOLIDE, AMBRINOL95, ANDRANE, APHERMATE, APPLELIDE, BACDANOL®, BERGAMAL, BETA IONONEEPOXIDE, BETA NAPHTHYL ISO-BUTYL ETHER, BICYCLONONALACTONE, BORNAFIX®,CANTHOXAL, CASHMERAN®, CASHMERAN® VELVET, CASSIFFIX®, CEDRAFIX,CEDRAMBER®, CEDRYL ACETATE, CELESTOLIDE, CINNAMALVA, CITRAL DIMETHYLACETATE, CITROLATE™, CITRONELLOL 700, CITRONELLOL 950, CITRONELLOLCOEUR, CITRONELLYL ACETATE, CITRONELLYL ACETATE PURE, CITRONELLYLFORMATE, CLARYCET, CLONAL, CONIFERAN, CONIFERAN PURE, CORTEX ALDEHYDE50% PEOMOSA, CYCLABUTE, CYCLACET®, CYCLAPROP®, CYCLEMAX™, CYCLOHEXYLETHYL ACETATE, DAMASCOL, DELTA DAMASCONE, DIHYDRO CYCLACET, DIHYDROMYRCENOL, DIHYDRO TERPINEOL, DIHYDRO TERPINYL ACETATE, DIMETHYLCYCLORMOL, DIMETHYL OCTANOL PQ, DIMYRCETOL, DIOLA, DIPENTENE, DULCINYL®RECRYSTALLIZED, ETHYL-3-PHENYL GLYCIDATE, FLEURAMONE, FLEURANIL, FLORALSUPER, FLORALOZONE, FLORIFFOL, FRAISTONE, FRUCTONE, GALAXOLIDE® 50,GALAXOLIDE® 50 BB, GALAXOLIDE® 50 IPM, GALAXOLIDE® UNDILUTED,GALBASCONE, GERALDEHYDE, GERANIOL 5020, GERANIOL 600 TYPE, GERANIOL 950,GERANIOL 980 (PURE), GERANIOL CFT COEUR, GERANIOL COEUR, GERANYL ACETATECOEUR, GERANYL ACETATE, PURE, GERANYL FORMATE, GRISALVA, GUAIYL ACETATE,HELIONAL™, HERBAC, HERBALIME™, HEXADECANOLIDE, HEXALON, HEXENYLSALICYLATE CIS 3-, HYACINTH BODY, HYACINTH BODY NO. 3, HYDRATROPICALDEHYDE.DMA, HYDROXYOL, INDOLAROME, INTRELEVEN ALDEHYDE, INTRELEVENALDEHYDE SPECIAL, IONONE ALPHA, IONONE BETA, ISO CYCLO CITRAL, ISO CYCLOGERANIOL, ISO E SUPER®, ISOBUTYL QUINOLINE, JASMAL, JESSEMAL®,KHARISMAL®, KHARISMAL® SUPER, KHUSINIL, KOAVONE®, KOHINOOL®, LIFFAROME™,LIMOXAL, LINDENOL™, LYRAL®, LYRAME SUPER, MANDARIN ALD 10% TRI ETH,CITR, MARITIMA, MCK CHINESE, MEIJIFF™, MELAFLEUR, MELOZONE, METHYLANTHRANILATE, METHYL IONONE ALPHA EXTRA, METHYL IONONE GAMMA A, METHYLIONONE GAMMA COEUR, METHYL IONONE GAMMA PURE, METHYL LAVENDER KETONE,MONTAVERDI®, MUGUESIA, MUGUET ALDEHYDE 50, MUSK Z4, MYRAC ALDEHYDE,MYRCENYL ACETATE, NECTARATE™, NEROL 900, NERYL ACETATE, OCIMENE,OCTACETAL, ORANGE FLOWER ETHER, ORIVONE, ORRINIFF 25%, OXASPIRANE,OZOFLEUR, PAMPLEFLEUR®, PEOMOSA, PHENOXANOL®, PICONIA, PRECYCLEMONE B,PRENYL ACETATE, PRISMANTOL, RESEDA BODY, ROSALVA, ROSAMUSK, SANJINOL,SANTALIFF™, SYVERTAL, TERPINEOL, TERPINOLENE 20, TERPINOLENE 90 PQ,TERPINOLENE RECT., TERPINYL ACETATE, TERPINYL ACETATE JAX, TETRAHYDRO,MUGUOL®, TETRAHYDRO MYRCENOL, TETRAMERAN, TIMBERSILK™, TOBACAROL,TRIMOFIX® O TT, TRIPLAL®, TRISAMBER®, VANORIS, VERDOX™, VERDOX™ HC,VERTENEX®, VERTENEX® HC, VERTOFIX® COEUR, VERTOLIFF, VERTOLIFF ISO,VIOLIFF, VIVALDIE, ZENOLIDE, ABS INDIA 75 PCT MIGLYOL, ABS MOROCCO 50PCT DPG, ABS MOROCCO 50 PCT TEC, ABSOLUTE FRENCH, ABSOLUTE INDIA,ABSOLUTE MD 50 PCT BB, ABSOLUTE MOROCCO, CONCENTRATE PG, TINCTURE 20PCT, AMBERGRIS, AMBRETTE ABSOLUTE, AMBRETTE SEED OIL, ARMOISE OIL 70 PCTTHUYONE, BASIL ABSOLUTE GRAND VERT, BASIL GRAND VERT ABS MD, BASIL OILGRAND VERT, BASIL OIL VERVEINA, BASIL OIL VIETNAM, BAY OIL TERPENELESS,BEESWAX ABS N G, BEESWAX ABSOLUTE, BENZOIN RESINOID SIAM, BENZOINRESINOID SIAM 50 PCT DPG, BENZOIN RESINOID SIAM 50 PCT PG, BENZOINRESINOID SIAM 70.5 PCT TEC, BLACKCURRANT BUD ABS 65 PCT PG, BLACKCURRANTBUD ABS MD 37 PCT TEC, BLACKCURRANT BUD ABS MIGLYOL, BLACKCURRANT BUDABSOLUTE BURGUNDY, BOIS DE ROSE OIL, BRAN ABSOLUTE, BRAN RESINOID, BROOMABSOLUTE ITALY, CARDAMOM GUATEMALA CO2 EXTRACT, CARDAMOM OIL GUATEMALA,CARDAMOM OIL INDIA, CARROT HEART, CASSIE ABSOLUTE EGYPT, CASSIE ABSOLUTEMD 50 PCT IPM, CASTOREUM ABS 90 PCT TEC, CASTOREUM ABS C 50 PCT MIGLYOL,CASTOREUM ABSOLUTE, CASTOREUM RESINOID, CASTOREUM RESINOID 50 PCT DPG,CEDROL CEDRENE, CEDRUS ATLANTICA OIL REDIST, CHAMOMILE OIL ROMAN,CHAMOMILE OIL WILD, CHAMOMILE OIL WILD LOW LIMONENE, CINNAMON BARK OILCEYLAN, CISTE ABSOLUTE, CISTE ABSOLUTE COLORLESS, CITRONELLA OIL ASIAIRON FREE, CIVET ABS 75 PCT PG, CIVET ABSOLUTE, CIVET TINCTURE 10 PCT,CLARY SAGE ABS FRENCH DECOL, CLARY SAGE ABSOLUTE FRENCH, CLARY SAGEC′LESS 50 PCT PG, CLARY SAGE OIL FRENCH, COPAIBA BALSAM, COPAIBA BALSAMOIL, CORIANDER SEED OIL, CYPRESS OIL, CYPRESS OIL ORGANIC, DAVANA OIL,GALBANOL, GALBANUM ABSOLUTE COLORLESS, GALBANUM OIL, GALBANUM RESINOID,GALBANUM RESINOID 50 PCT DPG, GALBANUM RESINOID HERCOLYN BHT, GALBANUMRESINOID TEC BHT, GENTIANE ABSOLUTE MD 20 PCT BB, GENTIANE CONCRETE,GERANIUM ABS EGYPT MD, GERANIUM ABSOLUTE EGYPT, GERANIUM OIL CHINA,GERANIUM OIL EGYPT, GINGER OIL 624, GINGER OIL RECTIFIED SOLUBLE,GUAIACWOOD HEART, HAY ABS MD 50 PCT BB, HAY ABSOLUTE, HAY ABSOLUTE MD 50PCT TEC, HEALINGWOOD, HYSSOP OIL ORGANIC, IMMORTELLE ABS YUGO MD 50 PCTTEC, IMMORTELLE ABSOLUTE SPAIN, IMMORTELLE ABSOLUTE YUGO, JASMIN ABSINDIA MD, JASMIN ABSOLUTE EGYPT, JASMIN ABSOLUTE INDIA, ASMIN ABSOLUTEMOROCCO, JASMIN ABSOLUTE SAMBAC, JONQUILLE ABS MD 20 PCT BB, JONQUILLEABSOLUTE France, JUNIPER BERRY OIL FLG, JUNIPER BERRY OIL RECTIFIEDSOLUBLE, LABDANUM RESINOID 50 PCT TEC, LABDANUM RESINOID BB, LABDANUMRESINOID MD, LABDANUM RESINOID MD 50 PCT BB, LAVANDIN ABSOLUTE H,LAVANDIN ABSOLUTE MD, LAVANDIN OIL ABRIAL ORGANIC, LAVANDIN OIL GROSSOORGANIC, LAVANDIN OIL SUPER, LAVENDER ABSOLUTE H, LAVENDER ABSOLUTE MD,LAVENDER OIL COUMARIN FREE, LAVENDER OIL COUMARIN FREE ORGANIC, LAVENDEROIL MAILLETTE ORGANIC, LAVENDER OIL MT, MACE ABSOLUTE BB, MAGNOLIAFLOWER OIL LOW METHYL EUGENOL, MAGNOLIA FLOWER OIL, MAGNOLIA FLOWER OILMD, MAGNOLIA LEAF OIL, MANDARIN OIL MD, MANDARIN OIL MD BHT, MATEABSOLUTE BB, MOSS TREE ABSOLUTE MD TEX IFRA 43, MOSS-OAK ABS MD TEC IFRA43, MOSS-OAK ABSOLUTE IFRA 43, MOSS-TREE ABSOLUTE MD IPM IFRA 43, MYRRHRESINOID BB, MYRRH RESINOID MD, MYRRH RESINOID TEC, MYRTLE OIL IRONFREE, MYRTLE OIL TUNISIA RECTIFIED, NARCISSE ABS MD 20 PCT BB, NARCISSEABSOLUTE FRENCH, NEROLI OIL TUNISIA, NUTMEG OIL TERPENELESS, OEILLETABSOLUTE, OLIBANUM RESINOID, OLIBANUM RESINOID BB, OLIBANUM RESINOIDDPG, OLIBANUM RESINOID EXTRA 50 PCT DPG, OLIBANUM RESINOID MD, OLIBANUMRESINOID MD 50 PCT DPG, OLIBANUM RESINOID TEC, OPOPONAX RESINOID TEC,ORANGE BIGARADE OIL MD BHT, ORANGE BIGARADE OIL MD SCFC, ORANGE FLOWERABSOLUTE TUNISIA, ORANGE FLOWER WATER ABSOLUTE TUNISIA, ORANGE LEAFABSOLUTE, ORANGE LEAF WATER ABSOLUTE TUNISIA, ORRIS ABSOLUTE ITALY,ORRIS CONCRETE 15 PCT IRONE, ORRIS CONCRETE 8 PCT IRONE, ORRIS NATURAL15 PCT IRONE 4095C, ORRIS NATURAL 8 PCT IRONE 2942C, ORRIS RESINOID,OSMANTHUS ABSOLUTE, OSMANTHUS ABSOLUTE MD 50 PCT BB, PATCHOULI HEART N°3, PATCHOULI OIL INDONESIA, PATCHOULI OIL INDONESIA IRON FREE, PATCHOULIOIL INDONESIA MD, PATCHOULI OIL REDIST, PENNYROYAL HEART, PEPPERMINTABSOLUTE MD, PETITGRAIN BIGARADE OIL TUNISIA, PETITGRAIN CITRONNIER OIL,PETITGRAIN OIL PARAGUAY TERPENELESS, PETITGRAIN OIL TERPENELESS STAB,PIMENTO BERRY OIL, PIMENTO LEAF OIL, RHODINOL EX GERANIUM CHINA, ROSEABS BULGARIAN LOW METHYL EUGENOL, ROSE ABS MOROCCO LOW METHYL EUGENOL,ROSE ABS TURKISH LOW METHYL EUGENOL, ROSE ABSOLUTE, ROSE ABSOLUTEBULGARIAN, ROSE ABSOLUTE DAMASCENA, ROSE ABSOLUTE MD, ROSE ABSOLUTEMOROCCO, ROSE ABSOLUTE TURKISH, ROSE OIL BULGARIAN, ROSE OIL DAMASCENALOW METHYL EUGENOL, ROSE OIL TURKISH, ROSEMARY OIL CAMPHOR ORGANIC,ROSEMARY OIL TUNISIA, SANDALWOOD OIL INDIA, SANDALWOOD OIL INDIARECTIFIED, SANTALOL, SCHINUS MOLLE OIL, ST JOHN BREAD TINCTURE 10 PCT,STYRAX RESINOID, STYRAX RESINOID, TAGETE OIL, TEA TREE HEART, TONKA BEANABS 50 PCT SOLVENTS, TONKA BEAN ABSOLUTE, TUBEROSE ABSOLUTE INDIA,VETIVER HEART EXTRA, VETIVER OIL HAITI, VETIVER OIL HAITI MD, VETIVEROIL JAVA, VETIVER OIL JAVA MD, VIOLET LEAF ABSOLUTE EGYPT, VIOLET LEAFABSOLUTE EGYPT DECOL, VIOLET LEAF ABSOLUTE FRENCH, VIOLET LEAF ABSOLUTEMD 50 PCT BB, WORMWOOD OIL TERPENELESS, YLANG EXTRA OIL, YLANG III OILand combinations of these.

The colorants can be among those listed in the Color Index Internationalby the Society of Dyers and Colourists. Colorants include dyes andpigments and include those commonly used for coloring textiles, paints,inks and inkjet inks. Some colorants that can be utilized includecarotenoids, arylide yellows, diarylide yellows, ß-naphthols, naphthols,benzimidazolones, disazo condensation pigments, pyrazolones, nickel azoyellow, phthalocyanines, quinacridones, perylenes and perinones,isoindolinone and isoindoline pigments, triarylcarbonium pigments,diketopyrrolo-pyrrole pigments, thioindigoids. Cartenoids include e.g.,alpha-carotene, beta-carotene, gamma-carotene, lycopene, lutein andastaxanthin Annatto extract, Dehydrated beets (beet powder),Canthaxanthin, Caramel, Apo-8′-carotenal, Cochineal extract, Carmine,Sodium copper chlorophyllin, Toasted partially defatted cookedcottonseed flour, Ferrous gluconate, Ferrous lactate, Grape colorextract, Grape skin extract (enocianina), Carrot oil, Paprika, Paprikaoleoresin, Mica-based pearlescent pigments, Riboflavin, Saffron,Titanium dioxide, carbon black, self-dispersed carbon, Tomato lycopeneextract; tomato lycopene concentrate, Turmeric, Turmeric oleoresin, FD&CBlue No. 1, FD&C Blue No. 2, FD&C Green No. 3, Orange B, Citrus Red No.2, FD&C Red No. 3, FD&C Red No. 40, FD&C Yellow No. 5, FD&C Yellow No.6, Alumina (dried aluminum hydroxide), Calcium carbonate, Potassiumsodium copper chlorophyllin (chlorophyllin-copper complex),Dihydroxyacetone, Bismuth oxychloride, Ferric ammonium ferrocyanide,Ferric ferrocyanide, Chromium hydroxide green, Chromium oxide greens,Guanine, Pyrophyllite, Talc, Aluminum powder, Bronze powder, Copperpowder, Zinc oxide, D&C Blue No. 4, D&C Green No. 5, D&C Green No. 6,D&C Green No. 8, D&C Orange No. 4, D&C Orange No. 5, D&C Orange No. 10,D&C Orange No. 11, FD&C Red No. 4, D&C Red No. 6, D&C Red No. 7, D&C RedNo. 17, D&C Red No. 21, D&C Red No. 22, D&C Red No. 27, D&C Red No. 28,D&C Red No. 30, D&C Red No. 31, D&C Red No. 33, D&C Red No. 34, D&C RedNo. 36, D&C Red No. 39, D&C Violet No. 2, D&C Yellow No. 7, Ext. D&CYellow No. 7, D&C Yellow No. 8, D&C Yellow No. 10, D&C Yellow No. 11,D&C Black No. 2, D&C Black No. 3 (3), D&C Brown No. 1, Ext. D&C,Chromium-cobalt-aluminum oxide, Ferric ammonium citrate, Pyrogallol,Logwood extract, 1,4-Bis[(2-hydroxy-ethyl)amino]-9,10-anthracenedionebis(2-propenoic)ester copolymers, 1,4-Bis[(2-methylphenyl)amino]-9,10-anthracenedione,1,4-Bis[4-(2-methacryloxyethyl) phenylamino] anthraquinone copolymers,Carbazole violet, Chlorophyllin-copper complex, Chromium-cobalt-aluminumoxide, C.I. Vat Orange 1, 2-[[2,5-Diethoxy-4-[(4-methylphenyl)thiol]phenyl]azo]-1,3,5-benzenetriol, 16,23-Dihydrodinaphtho [2,3-a:2′,3′-i]naphth [2′,3′:6,7] indolo [2,3-c] carbazole-5,10,15,17,22,24-hexone,N,N′-(9,10-Dihydro-9,10-dioxo-1,5-anthracenediyl) bisbenzamide,7,16-Dichloro-6,15-dihydro-5,9,14,18-anthrazinetetrone,16,17-Dimethoxydinaphtho (1,2,3-cd:3′,2′,1′-lm) perylene-5,10-dione,Poly(hydroxyethyl methacrylate)-dye copolymers (3), Reactive Black 5,Reactive Blue 21, Reactive Orange 78, Reactive Yellow 15, Reactive BlueNo. 19, Reactive Blue No. 4, C.I. Reactive Red 11, C.I. Reactive Yellow86, C.I. Reactive Blue 163, C.I. Reactive Red 180,4-[(2,4-dimethylphenyl)azo]-2,4-dihydro-5-methyl-2-phenyl-3H-pyrazol-3-one(solvent Yellow 18), 6-Ethoxy-2-(6-ethoxy-3-oxobenzo[b]thien-2(3H)-ylidene) benzo[b]thiophen-3(2H)-one, Phthalocyanine green,Vinyl alcohol/methyl methacrylate-dye reaction products, C.I. ReactiveRed 180, C.I. Reactive Black 5, C.I. Reactive Orange 78, C.I. ReactiveYellow 15, C.I. Reactive Blue 21, Disodium1-amino-4-[[4-[(2-bromo-1-oxoallyl)amino]-2-sulphonatophenyl]amino]-9,10-dihydro-9,10-dioxoanthracene-2-sulphonate(Reactive Blue 69), D&C Blue No. 9, [Phthalocyaninato(2-)] copper andmixtures of these.

For example, a fragrance, e.g., natural wood fragrance, can becompounded into the resin used to make the composite. In someimplementations, the fragrance is compounded directly into the resin asan oil. For example, the oil can be compounded into the resin using aroll mill, e.g., a Banbury® mixer or an extruder, e.g., a twin-screwextruder with counter-rotating screws. An example of a Banbury® mixer isthe F-Series Banbury® mixer, manufactured by Farrel. An example of atwin-screw extruder is the WP ZSK 50 MEGACOMPOUNDER™, manufactured byCoperion, Stuttgart, Germany After compounding, the scented resin can beadded to the fibrous material and extruded or molded. Alternatively,master batches of fragrance-filled resins are available commerciallyfrom International Flavors and Fragrances, under the trade namePOLYIFF™. In some embodiments, the amount of fragrance in the compositeis between about 0.005% by weight and about 10% by weight, e.g., betweenabout 0.1% and about 5% or 0.25% and about 2.5%. Other natural woodfragrances include evergreen or redwood. Other fragrances includepeppermint, cherry, strawberry, peach, lime, spearmint, cinnamon, anise,basil, bergamot, black pepper, camphor, chamomile, citronella,eucalyptus, pine, fir, geranium, ginger, grapefruit, jasmine, juniperberry, lavender, lemon, mandarin, marjoram, musk, myrrh, orange,patchouli, rose, rosemary, sage, sandalwood, tea tree, thyme,wintergreen, ylang ylang, vanilla, new car or mixtures of thesefragrances. In some embodiments, the amount of fragrance in the fibrousmaterial-fragrance combination is between about 0.005% by weight andabout 20% by weight, e.g., between about 0.1% and about 5% or 0.25% andabout 2.5%. Even other fragrances and methods are described U.S. Pat.No. 8,074,910 issued Dec. 13, 2011, the entire disclosure of whichincorporated herein by reference.

Uses of PLA And PLA Copolymers

Some uses of PLA and PLA containing materials include: personal careitems (e.g., tissues, towels, diapers), green packaging, garden(compostable pots), consumer electronics (e.g., laptop and mobile phonecasings), appliances, food packaging, disposable packaging (e.g., foodcontainers and drink bottles), garbage bags (e.g., waste compostablebags), mulch films, controlled release matrices and containers (e.g.,for fertilizers, pesticides, herbicides, nutrients, pharmaceuticals,flavoring agents, foods), shopping bags, general purpose film, high heatfilm, heat seal layer, surface coating, disposable tableware (e.g.,plates, cups, forks, knives, spoons, sporks, bowls), automotive parts(e.g., panels, fabrics, under hood covers), carpet fibers, clothingfibers (e.g., for garments, sportswear, footwear), biomedicalapplications (e.g., surgical sutures, implants, scaffolding, drugdelivery systems, dialysis equipment) and engineering plastics.

Other uses/industrial sectors that can benefit from the use of PLA andPLA derivatives (e.g., elastomers) include IT and software, electronics,geoscience (e.g., oil and gas), engineering, aerospace (e.g., arm rests,seats, panels), telecommunications (e.g., headsets), chemicalmanufacturing, transportation such as automotive (e.g., dashboards,panels, tires, wheels), materials and steel, consumer packaged goods,wires and cables.

Other Advantages of PLA and PLA Copolymers

PLA is bio-based and can be composted, recycled, used as a fuel(incinerated). Some of the degradation reactions include thermaldegradation, hydrolytic degradation and biotic degradations.

PLA can be thermally degraded. For example, at high temperatures (e.g.,between about 200-300° C., about 230-260° C.). The reactions involved inthe thermal degradation of PLA can follow different mechanisms such asthermo hydrolysis, zipper-like depolymerization (e.g., in the presenceof residual catalysts), thermo-oxidative degradation.Transesterification reactions can also operate on the polymer causingbond breaking and/or bond making.

PLA also can undergo hydrolytic degradation. Hydrolytic degradationincludes chain scission producing shorter polymers, oligomers andeventually the monomer lactic acid can be released. Hydrolysis can beassociated with thermal and biotic degradation. The process can beeffected by various parameters such as the PLA structure, its molecularweight and distribution, its morphology (e.g., crystallinity), the shapeof the sample (e.g., isolated thin samples or comminuted samples candegrade faster), the thermal and mechanical history (e.g., processing)and the hydrolysis conditions (e.g., temperature, agitation,comminution). The hydrolysis of PLA starts with a water uptake phase,followed by hydrolytic splitting of the ester bonds. The amorphous partsof the polyesters can be hydrolyzed faster than the crystalline regionsbecause of the higher water uptake and mobility of chain segments inthese regions. In a second stage, the crystalline regions of PLA arehydrolyzed.

PLA can also undergo biotic degradation. This degradation can occur forexample, in a mammalian body, and has useful implications for °degradable stitching and can have detrimental implications to othersurgical implants. Enzymes, such as proteinase K and pronase can beutilized.

During composting, PLA can go through several degradation stages. Forexample, an initial stage can occur due to exposure to moisture whereinthe degradation is abiotic and the PLA degrades by hydrolysis. Thisstage can be accelerated by the presence of acids and bases and elevatedtemperatures. The first stage can lead to embrittlement of the polymerwhich can facilitate the diffusion of PLA out of the bulk polymers. Theoligomers can then be attacked by micro-organisms. Organisms can degradethe oligomers and lactic acid, leading to CO₂ and water. Time for thisdegradation is on the order of about one to a few years depending on thefactors previously mentioned. The degradation time is several orders ofmagnitude faster than typical petroleum based plastic such aspolyethylene (e.g., on the order of hundreds of years).

PLA can also be recycled. For example, the PLA can be hydrolyzed tolactide acid, purified and re-polymerized. Unlike other recyclableplastics such as PET and HDPE, PLA does not need to be down-graded tomake a product of diminished value (e.g., from a bottle to decking orcarpet). PLA can be in theory recycled indefinitely. Optionally, PLA canbe re-used and downgraded for several generations and then converted toPLA and re-polymerized.

PLA can also be used as a fuel, for example, for energy production. PLAcan have high heat content e.g., up to about 8400 BTU. Incineration ofpure PLA only releases carbon dioxide and water. Combinations with otheringredients typically amount to less than 1 ppm of non PLA residuals(e.g., ash). Thus the combustion of PLA is cleaner than other renewablefuels, e.g. wood. [00172] PLA can have high gloss, high transparency,high clarity, high stiffness, can be UV stable, non-allergenic, highflavor and aroma barrier properties, easy to blend, easy to mold, easyto shape, easy to emboss, easy to print on, lightweight, compostable.

PLA can also be printed on. For example, by lithographic, ink-jetprinting, laser printing, fixed-type printing, roller printing. Some PLAcan also be written on, for example, using a pen.

Processing as described herein can also include irradiation. Forexample, irradiation with between about 1 and 150 Mrad radiation (e.g.,for example, any range as described herein) can improve thecompostability and recyclability of PLA and PLA containing materials.

Radiation Treatment

The feedstock (e.g., cellulosic, lignocellulosic, PLA, PLA derivativesand combinations of these) can be treated with electron bombardment tomodify its structure, for example, to reduce its recalcitrance or crosslink the structures. Such treatment can, for example, reduce the averagemolecular weight of the feedstock, change the crystalline structure ofthe feedstock, and/or increase the surface area and/or porosity of thefeedstock. Alternatively this treatment can produce radicals that can besites for cross-linking, grafting and/or functionalization.

Electron bombardment via an electron beam is generally preferred,because it provides very high throughput. Accelerators used toaccelerate the particles can be electrostatic DC, electrodynamic DC, RFlinear, magnetic induction linear or continuous wave. For example,cyclotron type accelerators are available from IBA, Belgium, such as theRHODOTRON™ system, while DC type accelerators are available from RDI,now IBA Industrial, such as the DYNAMITRON®. Ions and ion acceleratorsare discussed in Introductory Nuclear Physics, Kenneth S. Krane, JohnWiley & Sons, Inc. (1988), Krsto Prelec, FIZIKA B 6 (1997) 4, 177-206,Chu, William T., “Overview of Light-Ion Beam Therapy”, Columbus-Ohio,ICRU-IAEA Meeting, 18-20 Mar. 2006, Iwata, Y. et al.,“Alternating-Phase-Focused IH-DTL for Heavy-Ion Medical Accelerators”,Proceedings of EPAC 2006, Edinburgh, Scotland, and Leitner, C. M. etal., “Status of the Superconducting ECR Ion Source Venus”, Proceedingsof EPAC 2000, Vienna, Austria.

Electron bombardment may be performed using an electron beam device thathas a nominal energy of less than 10 MeV, e.g., less than 7 MeV, lessthan 5 MeV, or less than 2 MeV, e.g., from about 0.5 to 1.5 MeV, fromabout 0.8 to 1.8 MeV, or from about 0.7 to 1 MeV. In someimplementations the nominal energy is about 500 to 800 keV.

The electron beam may have a relatively high total beam power (thecombined beam power of all accelerating heads, or, if multipleaccelerators are used, of all accelerators and all heads), e.g., atleast 25 kW, e.g., at least 30, 40, 50, 60, 65, 70, 80, 100, 125, or150, 250, 300 kW. In some cases, the power is even as high as 500 kW,750 kW, or even 1000 kW or more. In some cases the electron beam has abeam power of 1200 kW or more, e.g., 1400, 1600, 1800, or even 3000 kW.The electron beam may have a total beam power of 25 to 3000 kW.Alternatively, the electron beam may have a total beam power of 75 to1500 kW. Optionally, the electron beam may have a total beam power of100 to 1000 kW. Alternatively, the electron beam may have a total beampower of 100 to 400 kW.

This high total beam power is usually achieved by utilizing multipleaccelerating heads. For example, the electron beam device may includetwo, four, or more accelerating heads. The use of multiple heads, eachof which has a relatively low beam power, prevents excessive temperaturerise in the material, thereby preventing burning of the material, andalso increases the uniformity of the dose through the thickness of thelayer of material.

It is generally preferred that the bed of feedstock material has arelatively uniform thickness. In some embodiments the thickness is lessthan about 1 inch (e.g., less than about 0.75 inches, less than about0.5 inches, less than about 0.25 inches, less than about 0.1 inches,between about 0.1 and 1 inch, between about 0.2 and 0.3 inches).

In some implementations, it is desirable to cool the material during andbetween dosing the material with electron bombardment. For example, thematerial can be cooled while it is conveyed, for example, by a screwextruder, vibratory conveyor or other conveying equipment. For example,cooling while conveying is described International App. No.PCT/US2014/021609 filed Mar. 7, 2014 and International App. No.PCT/US2014/021632 filed Mar. 7, 2014, the entire descriptions of whichare herein incorporated by reference.

To reduce the energy required by the recalcitrance-reducing process, itis desirable to treat the material as quickly as possible. In general,the treatment be performed at a dose rate of greater than about 0.25Mrad per second, e.g., greater than about 0.5, 0.75, 1, 1.5, 2, 5, 7,10, 12, 15, or even greater than about 20 Mrad per second, e.g., about0.25 to 30 Mrad per second. Alternately, the treatment is performed at adose rate of 0.5 to 20 Mrad per second. Optionally, the treatment isperformed at a dose rate of 0.75 to 15 Mrad per second. Alternately, thetreatment is performed at a dose rate of 1 to 5 Mrad per second.Optionally, the treatment is performed at a dose rate of 1-3 Mrad persecond or alternatively 1-2 Mrad per second. Higher dose rates allow ahigher throughput for a target (e.g., the desired) dose. Higher doserates generally require higher line speeds, to avoid thermaldecomposition of the material. In one implementation, the accelerator isset for 3 MeV, 50 mA beam current, and the line speed is 24 feet/minute,for a sample thickness of about 20 mm (e.g., comminuted corn cobmaterial with a bulk density of 0.5 g/cm³).

In some embodiments, electron bombardment is performed until thematerial receives a total dose of at least 0.1 Mrad, 0.25 Mrad, 1 Mrad,5 Mrad, e.g., at least 10, 20, 30 or at least 40 Mrad. In someembodiments, the treatment is performed until the material receives adose of from about 10 Mrad to about 50 Mrad, e.g., from about 20 Mrad toabout 40 Mrad, or from about 25 Mrad to about 30 Mrad. In someimplementations, a total dose of 25 to 35 Mrad is preferred, appliedideally over a couple of seconds, e.g., at 5 Mrad/pass with each passbeing applied for about one second. Applying a dose of greater than 7 to8 Mrad/pass can in some cases cause thermal degradation of the feedstockmaterial. Cooling can be applied before, after, or during irradiation.For example, the cooling methods, systems and equipment as described inthe following applications can be utilized: International App. No.PCT/US2014/021609 filed Mar. 7, 2014, and International App. No.PCT/US2013/064320 filed Oct. 10, 2013, the entire disclosures of whichare herein incorporated by reference.

Using multiple heads as discussed above, the material can be treated inmultiple passes, for example, two passes at 10 to 20 Mrad/pass, e.g., 12to 18 Mrad/pass, separated by a few seconds of cool-down, or threepasses of 7 to 12 Mrad/pass, e.g., 5 to 20 Mrad/pass, 10 to 40Mrad/pass, 9 to 11 Mrad/pass. As discussed herein, treating the materialwith several relatively low doses, rather than one high dose, tends toprevent overheating of the material and also increases dose uniformitythrough the thickness of the material. In some implementations, thematerial is stirred or otherwise mixed during or after each pass andthen smoothed into a uniform layer again before the next pass, tofurther enhance treatment uniformity.

In some embodiments, electrons are accelerated to, for example, a speedof greater than 75 percent of the speed of light, e.g., greater than 85,90, 95, or 99 percent of the speed of light.

In some embodiments, any processing described herein occurs on feedstockmaterial that remains dry as acquired or that has been dried, e.g.,using heat and/or reduced pressure. For example, in some embodiments,the cellulosic and/or lignocellulosic material has less than about 25wt. % retained water, measured at 25° C. and at fifty percent relativehumidity (e.g., less than about 20 wt. %, less than about 15 wt. %, lessthan about 14 wt. %, less than about 13 wt. %, less than about 12 wt. %,less than about 10 wt. %, less than about 9 wt. %, less than about 8 wt.%, less than about 7 wt. %, less than about 6 wt. %, less than about 5wt. %, less than about 4 wt. %, less than about 3 wt. %, less than about2 wt. %, less than about 1 wt. %, less than about 0.5 wt. %, less thanabout 15 wt. %.

In some embodiments, two or more electron sources are used, such as twoor more ionizing sources. For example, samples can be treated, in anyorder, with a beam of electrons, followed by gamma radiation and UVlight having wavelengths from about 100 nm to about 280 nm. In someembodiments, samples are treated with three ionizing radiation sources,such as a beam of electrons, gamma radiation, and energetic UV light.The biomass is conveyed through the treatment zone where it can bebombarded with electrons.

It may be advantageous to repeat the treatment to more thoroughly reducethe recalcitrance of the biomass and/or further modify the biomass. Inparticular, the process parameters can be adjusted after a first (e.g.,second, third, fourth or more) pass depending on the recalcitrance ofthe material. In some embodiments, a conveyor can be used which includesa circular system where the biomass is conveyed multiple times throughthe various processes described above. In some other embodiments,multiple treatment devices (e.g., electron beam generators) are used totreat the biomass multiple (e.g., 2, 3, 4 or more) times. In yet otherembodiments, a single electron beam generator may be the source ofmultiple beams (e.g., 2, 3, 4 or more beams) that can be used fortreatment of the biomass.

The effectiveness in changing the molecular/supermolecular structureand/or reducing the recalcitrance of the carbohydrate-containing biomassdepends on the electron energy used and the dose applied, while exposuretime depends on the power and dose. In some embodiments, the dose rateand total are adjusted so as not to destroy (e.g., char or burn) thebiomass material. For example, the carbohydrates should not be damagedin the processing so that they can be released from the biomass intact,e.g. as monomeric sugars.

In some embodiments, the treatment (with any electron source or acombination of sources) is performed until the material receives a doseof at least about 0.05 Mrad, e.g., at least about 0.1, 0.25, 0.5, 0.75,1.0, 2.5, 5.0, 7.5, 10.0, 15, 20, 25, 30, 40, 50, 60, 70, 80, 90, 100,125, 150, 175, or 200 Mrad. In some embodiments, the treatment isperformed until the material receives a dose of between 0.1-100 Mrad,1-200, 5-200, 10-200, 5-150, 50-150 Mrad, 5-100, 5-50, 5-40, 10-50,10-75, 15-50, 20-35 Mrad.

Radiation Opaque Materials

The invention can include processing the material in a vault and/orbunker that is constructed using radiation opaque materials. In someimplementations, the radiation opaque materials are selected to becapable of shielding the components from X-rays with high energy (shortwavelength), which can penetrate many materials. One important factor indesigning a radiation shielding enclosure is the attenuation length ofthe materials used, which will determine the required thickness for aparticular material, blend of materials, or layered structure. Theattenuation length is the penetration distance at which the radiation isreduced to approximately 1/e (e=Euler's number) times that of theincident radiation. Although virtually all materials are radiationopaque if thick enough, materials containing a high compositionalpercentage (e.g., density) of elements that have a high Z value (atomicnumber) have a shorter radiation attenuation length and thus, if suchmaterials are used, a thinner, lighter shielding can be provided.Examples of high Z value materials that are used in radiation shieldingare tantalum and lead. Another important parameter in radiationshielding is the halving distance, which is the thickness of aparticular material that will reduce gamma ray intensity by 50%. As anexample for X-ray radiation with an energy of 0.1 MeV the halvingthickness is about 15.1 mm for concrete and about 0.27 mm for lead,while with an X-ray energy of 1 MeV the halving thickness for concreteis about 44.45 mm and for lead is about 7.9 mm Radiation opaquematerials can be materials that are thick or thin so long as they canreduce the radiation that passes through to the other side. Thus, if itis desired that a particular enclosure have a low wall thickness, e.g.,for light weight or due to size constraints, the material chosen shouldhave a sufficient Z value and/or attenuation length so that its halvinglength is less than or equal to the desired wall thickness of theenclosure.

In some cases, the radiation opaque material may be a layered material,for example, having a layer of a higher Z value material, to providegood shielding, and a layer of a lower Z value material to provide otherproperties (e.g., structural integrity, impact resistance, etc.). Insome cases, the layered material may be a “graded-Z” laminate, e.g.,including a laminate in which the layers provide a gradient from high-Zthrough successively lower-Z elements. In some cases the radiationopaque materials can be interlocking blocks, for example, lead and/orconcrete blocks can be supplied by NELCO Worldwide (Burlington, Mass.),and reconfigurable vaults can be utilized as described in InternationalApp. No. PCT/US2014/021629 filed on Mar. 7, 2014 the entire disclosureof which is herein incorporated by reference.

A radiation opaque material can reduce the radiation passing through astructure (e.g., a wall, door, ceiling, enclosure, a series of these orcombinations of these) formed of the material by about at least about10%, (e.g., at least about 20%, at least about 30%, at least about 40%,at least about 50%, at least about 60%, at least about 70%, at leastabout 80%, at least about 90%, at least about 95%, at least about 96%,at least about 97%, at least about 98%, at least about 99%, at leastabout 99.9%, at least about 99.99%, at least about 99.999%) as comparedto the incident radiation. Therefore, an enclosure made of a radiationopaque material can reduce the exposure of equipment/system/componentsby the same amount. Radiation opaque materials can include stainlesssteel, metals with Z values above 25 (e.g., lead, iron), concrete, dirt,sand and combinations thereof. Radiation opaque materials can include abarrier in the direction of the incident radiation of at least about 1mm (e.g., 5 mm, 10 mm, 5 cm, 10 cm, 100 cm, 1 m, 10 m).

Electron Sources

Electrons interact via Coulomb scattering and bremsstrahlung radiationproduced by changes in the velocity of electrons. Electrons may beproduced by radioactive nuclei that undergo beta decay, such as isotopesof iodine, cesium, technetium, and iridium. Alternatively, an electrongun can be used as an electron source via thermionic emission andaccelerated through an accelerating potential. An electron gun generateselectrons, accelerates them through a large potential (e.g., greaterthan about 500 thousand, greater than about 1 million, greater thanabout 2 million, greater than about 5 million, greater than about 6million, greater than about 7 million, greater than about 8 million,greater than about 9 million, or even greater than 10 million volts) andthen scans them magnetically in the x-y plane, where the electrons areinitially accelerated in the z direction down the tube and extractedthrough a foil window. Scanning the electron beam is useful forincreasing the irradiation surface when irradiating materials, e.g., abiomass, that is conveyed through the scanned beam. Scanning theelectron beam also distributes the thermal load homogenously on thewindow and helps reduce the foil window rupture due to local heating bythe electron beam. Window foil rupture is a cause of significantdown-time due to subsequent necessary repairs and re-starting theelectron gun.

Various other irradiating devices may be used in the methods disclosedherein, including field ionization sources, electrostatic ionseparators, field ionization generators, thermionic emission sources,microwave discharge ion sources, recirculating or static accelerators,dynamic linear accelerators, van de Graaff accelerators, and foldedtandem accelerators. Such devices are disclosed, for example, in U.S.Pat. No. 7,931,784 to Medoff, the complete disclosure of which isincorporated herein by reference.

A beam of electrons can be used as the radiation source. A beam ofelectrons has the advantages of high dose rates (e.g., 1, 5, or even 10Mrad per second), high throughput, less containment, and lessconfinement equipment. Electron beams can also have high electricalefficiency (e.g., 80%), allowing for lower energy usage relative toother radiation methods, which can translate into a lower cost ofoperation and lower greenhouse gas emissions corresponding to thesmaller amount of energy used. Electron beams can be generated, e.g., byelectrostatic generators, cascade generators, transformer generators,low energy accelerators with a scanning system, low energy acceleratorswith a linear cathode, linear accelerators, and pulsed accelerators.

Electrons can also be more efficient at causing changes in the molecularstructure of carbohydrate-containing materials, for example, by themechanism of chain scission. In addition, electrons having energies of0.5-10 MeV can penetrate low density materials, such as the biomassmaterials described herein, e.g., materials having a bulk density ofless than 0.5 g/cm³, and a depth of 0.3-10 cm. Electrons as an ionizingradiation source can be useful, e.g., for relatively thin piles, layersor beds of materials, e.g., less than about 0.5 inch, e.g., less thanabout 0.4 inch, 0.3 inch, 0.25 inch, or less than about 0.1 inch. Insome embodiments, the energy of each electron of the electron beam isfrom about 0.3 MeV to about 2.0 MeV (million electron volts), e.g., fromabout 0.5 MeV to about 1.5 MeV, or from about 0.7 MeV to about 1.25 MeV.Methods of irradiating materials are discussed in U.S. Pat. App. Pub.2012/0100577 A1, filed Oct. 18, 2011, the entire disclosure of which isherein incorporated by reference.

Electron beam irradiation devices may be procured commercially from IonBeam Applications, Louvain-la-Neuve, Belgium or the Titan Corporation,San Diego, Calif. Typical electron energies can be 0.5 MeV, 1 MeV, 2MeV, 4.5 MeV, 7.5 MeV, or 10 MeV. Typical electron beam irradiationdevice power can be 1 KW, 5 KW, 10 KW, 20 KW, 50 KW, 60 KW, 70 KW, 80KW, 90 KW, 100 KW, 125 KW, 150 KW, 175 KW, 200 KW, 250 KW, 300 KW, 350KW, 400 KW, 450 KW, 500 KW, 600 KW, 700 KW, 800 KW, 900 KW or even 1000KW.

Tradeoffs in considering electron beam irradiation device powerspecifications include cost to operate, capital costs, depreciation, anddevice footprint. Tradeoffs in considering exposure dose levels ofelectron beam irradiation would be energy costs and environment, safety,and health (ESH) concerns. Typically, generators are housed in a vault,e.g., of lead or concrete, especially for production from X-rays thatare generated in the process. Tradeoffs in considering electron energiesinclude energy costs.

The electron beam irradiation device can produce either a fixed beam ora scanning beam. A scanning beam may be advantageous with large scansweep length and high scan speeds, as this would effectively replace alarge, fixed beam width. Further, available sweep widths of 0.5 m, 1 m,2 m or more are available. The scanning beam is preferred in mostembodiments described herein because of the larger scan width andreduced possibility of local heating and failure of the windows.

Electron Guns—Windows

The extraction system for an electron accelerator can include two windowfoils. Window foils are described in International App. No.PCT/US2013/064332 filed Oct. 10, 2013 the complete disclosure of whichis herein incorporated by reference. The cooling gas in the two foilwindow extraction system can be a pure gas or a mixture, for example,air, or a pure gas. In one embodiment the gas is an inert gas such asnitrogen, argon, helium and/or carbon dioxide. It is preferred to use agas rather than a liquid since energy losses to the electron beam areminimized Mixtures of pure gas can also be used, either pre-mixed ormixed in line prior to impinging on the windows or in the space betweenthe windows. The cooling gas can be cooled, for example, by using a heatexchange system (e.g., a chiller) and/or by using boil off from acondensed gas (e.g., liquid nitrogen, liquid helium).

When using an enclosure, the enclosed conveyor can also be purged withan inert gas so as to maintain an atmosphere at a reduced oxygen level.Keeping oxygen levels low avoids the formation of ozone which in someinstances is undesirable due to its reactive and toxic nature. Forexample, the oxygen can be less than about 20% (e.g., less than about10%, less than about 1%, less than about 0.1%, less than about 0.01%, oreven less than about 0.001% oxygen). Purging can be done with an inertgas including, but not limited to, nitrogen, argon, helium or carbondioxide. This can be supplied, for example, from a boil off of a liquidsource (e.g., liquid nitrogen or helium), generated or separated fromair in situ, or supplied from tanks. The inert gas can be recirculatedand any residual oxygen can be removed using a catalyst, such as acopper catalyst bed. Alternatively, combinations of purging,recirculating and oxygen removal can be done to keep the oxygen levelslow.

The enclosure can also be purged with a reactive gas that can react withthe biomass. This can be done before, during or after the irradiationprocess. The reactive gas can be, but is not limited to, nitrous oxide,ammonia, oxygen, ozone, hydrocarbons, aromatic compounds, amides,peroxides, azides, halides, oxyhalides, phosphides, phosphines, arsines,sulfides, thiols, boranes and/or hydrides. The reactive gas can beactivated in the enclosure, e.g., by irradiation (e.g., electron beam,UV irradiation, microwave irradiation, heating, IR radiation), so thatit reacts with the biomass. The biomass itself can be activated, forexample, by irradiation. Preferably the biomass is activated by theelectron beam, to produce radicals which then react with the activatedor unactivated reactive gas, e.g., by radical coupling or quenching.

Purging gases supplied to an enclosed conveyor can also be cooled, forexample, below about 25° C., below about 0° C., below about −40° C.,below about −80° C., below about −120° C. For example, the gas can beboiled off from a compressed gas such as liquid nitrogen or sublimedfrom solid carbon dioxide. As an alternative example, the gas can becooled by a chiller or part of or the entire conveyor can be cooled.

Heating and Throughput During Radiation Treatment

Several processes can occur in biomass when electrons from an electronbeam interact with matter in inelastic collisions. For example,ionization of the material, chain scission of polymers in the material,cross linking of polymers in the material, oxidation of the material,generation of X-rays (“Bremsstrahlung”) and vibrational excitation ofmolecules (e.g. phonon generation). Without being bound to a particularmechanism, the reduction in recalcitrance can be due to several of theseinelastic collision effects, for example, ionization, chain scission ofpolymers, oxidation and phonon generation. Some of the effects (e.g.,especially X-ray generation), necessitate shielding and engineeringbarriers, for example, enclosing the irradiation processes in a concrete(or other radiation opaque material) vault. Another effect ofirradiation, vibrational excitation, is equivalent to heating up thesample. Heating the sample by irradiation can help in recalcitrancereduction, but excessive heating can destroy the material, as will beexplained below.

The adiabatic temperature rise (ΔT) from adsorption of ionizingradiation is given by the equation: ΔT=D/Cp: where D is the average dosein KGy, Cp is the heat capacity in J/g ° C., and ΔT is the change intemperature in ° C. A typical dry biomass material will have a heatcapacity close to 2. Wet biomass will have a higher heat capacitydependent on the amount of water since the heat capacity of water isvery high (4.19 J/g ° C.). Metals have much lower heat capacities, forexample, 304 stainless steel has a heat capacity of 0.5 J/g ° C. Thetemperature change due to the instant adsorption of radiation in abiomass and stainless steel for various doses of radiation is shown inTable 1.

TABLE 1 Calculated Temperature increase for biomass and stainless steel.Dose (Mrad) Estimated Biomass ΔT (° C.) Steel ΔT (° C.)  10 50  200  50 250, Decomposition 1000 100  500, Decomposition 2000 150  750,Decomposition 3000 200 1000, Decomposition 4000

High temperatures can destroy and or modify the biopolymers in biomassso that the polymers (e.g., cellulose) are unsuitable for furtherprocessing. A biomass subjected to high temperatures can become dark,sticky and give off odors indicating decomposition. The stickiness caneven make the material hard to convey. The odors can be unpleasant andbe a safety issue. In fact, keeping the biomass below about 200° C. hasbeen found to be beneficial in the processes described herein (e.g.,below about 190° C., below about 180° C., below about 170° C., belowabout 160° C., below about 150° C., below about 140° C., below about130° C., below about 120° C., below about 110° C., between about 60° C.and 180° C., between about 60° C. and 160° C., between about 60° C. and150° C., between about 60° C. and 140° C., between about 60° C. and 130°C., between about 60° C. and 120° C., between about 80° C. and 180° C.,between about 100° C. and 180° C., between about 120° C. and 180° C.,between about 140° C. and 180° C., between about 160° C. and 180° C.,between about 100° C. and 140° C., between about 80° C. and 120° C.).

It has been found that irradiation above about 10 Mrad is desirable forthe processes described herein (e.g., reduction of recalcitrance). Ahigh throughput is also desirable so that the irradiation does notbecome a bottle neck in processing the biomass. The treatment isgoverned by a Dose rate equation: M=FP/D*time, where M is the mass ofirradiated material (Kg), F is the fraction of power that is adsorbed(unit less), P is the emitted power (KW=Voltage in MeV*Current in mA),time is the treatment time (sec) and D is the adsorbed dose (KGy). In anexemplary process where the fraction of adsorbed power is fixed, thePower emitted is constant and a set dosage is desired, the throughput(e.g., M, the biomass processed) can be increased by increasing theirradiation time. However, increasing the irradiation time withoutallowing the material to cool, can excessively heat the material asexemplified by the calculations shown above. Since biomass has a lowthermal conductivity (less than about 0.1 Wm⁻¹K⁻¹), heat dissipation isslow, unlike, for example, metals (greater than about 10 Wm⁻¹K⁻¹) whichcan dissipate energy quickly as long as there is a heat sink to transferthe energy to.

Electron Guns—Beam Stops

In some embodiments the systems and methods include a beam stop (e.g., ashutter). For example, the beam stop can be used to quickly stop orreduce the irradiation of material without powering down the electronbeam device. Alternatively the beam stop can be used while powering upthe electron beam, e.g., the beam stop can stop the electron beam untila beam current of a desired level is achieved. The beam stop can beplaced between the primary foil window and a secondary foil window. Forexample, the beam stop can be mounted so that it is movable, that is, sothat it can be moved into and out of the beam path. Even partialcoverage of the beam can be used, for example, to control the dose ofirradiation. The beam stop can be mounted to the floor, to a conveyorfor the biomass, to a wall, to the radiation device (e.g., at the scanhorn), or to any structural support. Preferably, the beam stop is fixedin relation to the scan horn so that the beam can be effectivelycontrolled by the beam stop. The beam stop can incorporate a hinge, arail, wheels, slots, or other means allowing for its operation in movinginto and out of the beam. The beam stop can be made of any material thatwill stop at least 5% of the electrons, e.g., at least 10%, 20%, 30%,40%, 50%, 60%, 70%, at least 80%, 85%, 90%, 91%, 92%, 93%, 94%, 95%,96%, 97%, 98%, 99% or even about 100% of the electrons.

The beam stop can be made of a metal including, but not limited to,stainless steel, lead, iron, molybdenum, silver, gold, titanium,aluminum, tin, or alloys of these, or laminates (layered materials) madewith such metals (e.g., metal-coated ceramic, metal-coated polymer,metal-coated composite, multilayered metal materials).

The beam stop can be cooled, for example, with a cooling fluid such asan aqueous solution or a gas. The beam stop can be partially orcompletely hollow, for example, with cavities. Interior spaces of thebeam stop can be used for cooling fluids and gases. The beam stop can beof any shape, including flat, curved, round, oval, square, rectangular,beveled and wedged shapes.

The beam stop can have perforations so as to allow some electronsthrough, thus controlling (e.g., reducing) the levels of radiationacross the whole area of the window, or in specific regions of thewindow. The beam stop can be a mesh formed, for example, from fibers orwires. Multiple beam stops can be used, together or independently, tocontrol the irradiation. The beam stop can be remotely controlled, e.g.,by radio signal or hard wired to a motor for moving the beam into or outof position.

Biomass Materials

Lignocellulosic materials include, but are not limited to, wood (e.g.,softwood, Pine softwood, Softwood, Softwood barks, Softwood stems,Spruce softwood, Hardwood, Willow Hardwood, aspen hardwood, BirchHardwood, Hardwood barks, Hardwood stems, pine cones, pine needles),particle board, chemical pulps, mechanical pulps, paper, waste paper,forestry wastes (e.g., sawdust, aspen wood, wood chips, leaves),grasses, (e.g., switchgrass, miscanthus, cord grass, reed canary grass,Coastal Bermuda grass), grain residues, (e.g., rice hulls, oat hulls,wheat chaff, barley hulls), agricultural waste (e.g., silage, canolastraw, wheat straw, barley straw, oat straw, rice straw, jute, hemp,flax, bamboo, sisal, abaca, corn cobs, corn stover, soybean stover, cornfiber, alfalfa, hay, coconut hair, nut shells, palm and coconut oilbyproducts), cotton, Cotton seed hairs, flax, sugar processing residues(e.g., bagasse, beet pulp, agave bagasse), algae, seaweed, manure (e.g.,Solid cattle manure, Swine waste), sewage, carrot processing waste,molasses spent wash, alfalfa biver and mixtures of any of these.

In some cases, the lignocellulosic material includes corncobs. Ground orhammermilled corncobs can be spread in a layer of relatively uniformthickness for irradiation, and after irradiation are easy to disperse inthe medium for further processing. To facilitate harvest and collection,in some cases the entire corn plant is used, including the corn stalk,corn kernels, and in some cases even the root system of the plant.

Advantageously, no additional nutrients (other than a nitrogen source,e.g., urea or ammonia) are required during fermentation of corncobs orcellulosic or lignocellulosic materials containing significant amountsof corncobs.

Corncobs, before and after comminution, are also easier to convey anddisperse, and have a lesser tendency to form explosive mixtures in airthan other cellulosic or lignocellulosic materials such as hay andgrasses.

Cellulosic materials include, for example, paper, paper products, paperwaste, paper pulp, pigmented papers, loaded papers, coated papers,filled papers, magazines, printed matter (e.g., books, catalogs,manuals, labels, calendars, greeting cards, brochures, prospectuses,newsprint), printer paper, polycoated paper, card stock, cardboard,paperboard, materials having a high a-cellulose content such as cotton,and mixtures of any of these. For example, paper products as describedin U.S. application Ser. No. 13/396,365 (“Magazine Feedstocks” by Medoffet al., filed Feb. 14, 2012), the full disclosure of which isincorporated herein by reference.

Cellulosic materials can also include lignocellulosic materials whichhave been partially or fully de-lignified.

In some instances other biomass materials can be utilized, for example,starchy materials. Starchy materials include starch itself, e.g., cornstarch, wheat starch, potato starch or rice starch, a derivative ofstarch, or a material that includes starch, such as an edible foodproduct or a crop. For example, the starchy material can be arracacha,buckwheat, banana, barley, cassava, kudzu, ocra, sago, sorghum, regularhousehold potatoes, sweet potato, taro, yams, or one or more beans, suchas favas, lentils or peas. Blends of any two or more starchy materialsare also starchy materials. Mixtures of starchy, cellulosic and orlignocellulosic materials can also be used. For example, a biomass canbe an entire plant, a part of a plant or different parts of a plant,e.g., a wheat plant, cotton plant, a corn plant, rice plant or a tree.The starchy materials can be treated by any of the methods describedherein.

Microbial materials include, but are not limited to, any naturallyoccurring or genetically modified microorganism or organism thatcontains or is capable of providing a source of carbohydrates (e.g.,cellulose), for example, protists, e.g., animal protists (e.g., protozoasuch as flagellates, amoeboids, ciliates, and sporozoa) and plantprotists (e.g., algae such alveolates, chlorarachniophytes,cryptomonads, euglenids, glaucophytes, haptophytes, red algae,stramenopiles, and viridiplantae). Other examples include seaweed,plankton (e.g., macroplankton, mesoplankton, microplankton,nanoplankton, picoplankton, and femtoplankton), phytoplankton, bacteria(e.g., gram positive bacteria, gram negative bacteria, andextremophiles), yeast and/or mixtures of these. In some instances,microbial biomass can be obtained from natural sources, e.g., the ocean,lakes, bodies of water, e.g., salt water or fresh water, or on land.Alternatively or in addition, microbial biomass can be obtained fromculture systems, e.g., large scale dry and wet culture and fermentationsystems.

In other embodiments, the biomass materials, such as cellulosic, starchyand lignocellulosic feedstock materials, can be obtained from transgenicmicroorganisms and plants that have been modified with respect to a wildtype variety. Such modifications may be, for example, through theiterative steps of selection and breeding to obtain desired traits in aplant. Furthermore, the plants can have had genetic material removed,modified, silenced and/or added with respect to the wild type variety.For example, genetically modified plants can be produced by recombinantDNA methods, where genetic modifications include introducing ormodifying specific genes from parental varieties, or, for example, byusing transgenic breeding wherein a specific gene or genes areintroduced to a plant from a different species of plant and/or bacteria.Another way to create genetic variation is through mutation breedingwherein new alleles are artificially created from endogenous genes. Theartificial genes can be created by a variety of ways including treatingthe plant or seeds with, for example, chemical mutagens (e.g., usingalkylating agents, epoxides, alkaloids, peroxides, formaldehyde),irradiation (e.g., X-rays, gamma rays, neutrons, beta particles, alphaparticles, protons, deuterons, UV radiation) and temperature shocking orother external stressing and subsequent selection techniques. Othermethods of providing modified genes is through error prone PCR and DNAshuffling followed by insertion of the desired modified DNA into thedesired plant or seed. Methods of introducing the desired geneticvariation in the seed or plant include, for example, the use of abacterial carrier, biolistics, calcium phosphate precipitation,electroporation, gene splicing, gene silencing, lipofection,microinjection and viral carriers. Additional genetically modifiedmaterials have been described in U.S. application Ser. No. 13/396,369filed Feb. 14, 2012 the full disclosure of which is incorporated hereinby reference. Any of the methods described herein can be practiced withmixtures of any biomass materials described herein.

Biomass Material Preparation—Mechanical Treatments

The biomass can be in a dry form, for example, with less than about 35%moisture content (e.g., less than about 20%, less than about 15%, lessthan about 10% less than about 5%, less than about 4%, less than about3%, less than about 2% or even less than about 1%). The biomass can alsobe delivered in a wet state, for example, as a wet solid, a slurry or asuspension with at least about 10 wt. % solids (e.g., at least about 20wt. %, at least about 30 wt. %, at least about 40 wt. %, at least about50 wt. %, at least about 60 wt. %, at least about 70 wt. %).

The processes disclosed herein can utilize low bulk density materials,for example, cellulosic or lignocellulosic feedstocks that have beenphysically pretreated to have a bulk density of less than about 0.75g/cm³, e.g., less than about 0.7, 0.65, 0.60, 0.50, 0.35, 0.25, 0.20,0.15, 0.10, 0.05 or less, e.g., less than about 0.025 g/cm³. Bulkdensity is determined using ASTM D1895B. Briefly, the method involvesfilling a measuring cylinder of known volume with a sample and obtaininga weight of the sample. The bulk density is calculated by dividing theweight of the sample in grams by the known volume of the cylinder incubic centimeters. If desired, low bulk density materials can bedensified, for example, by methods described in U.S. Pat. No. 7,971,809to Medoff, the full disclosure of which is hereby incorporated byreference.

In some cases, the pre-treatment processing includes screening of thebiomass material. Screening can be through a mesh or perforated platewith a desired opening size, for example, less than about 6.35 mm (¼inch, 0.25 inch), (e.g., less than about 3.18 mm (⅛ inch, 0.125 inch),less than about 1.59 mm ( 1/16 inch, 0.0625 inch), is less than about0.79 mm ( 1/32 inch, 0.03125 inch), e.g., less than about 0.51 mm ( 1/50inch, 0.02000 inch), less than about 0.40 mm ( 1/64 inch, 0.015625inch), less than about 0.23 mm (0.009 inch), less than about 0.20 mm (1/128 inch, 0.0078125 inch), less than about 0.18 mm (0.007 inch), lessthan about 0.13 mm (0.005 inch), or even less than about 0.10 mm ( 1/256inch, 0.00390625 inch)). In one configuration the desired biomass fallsthrough the perforations or screen and thus biomass larger than theperforations or screen are not irradiated. These larger materials can bere-processed, for example, by comminuting, or they can simply be removedfrom processing. In another configuration, material that is larger thanthe perforations is irradiated and the smaller material is removed bythe screening process or recycled. In this kind of a configuration, theconveyor itself (for example, a part of the conveyor) can be perforatedor made with a mesh. For example, in one particular embodiment thebiomass material may be wet and the perforations or mesh allow water todrain away from the biomass before irradiation.

Screening of material can also be by a manual method, for example, by anoperator or mechanoid (e.g., a robot equipped with a color, reflectivityor other sensor) that removes unwanted material. Screening can also beby magnetic screening wherein a magnet is disposed near the conveyedmaterial and the magnetic material is removed magnetically.

Optional pre-treatment processing can include heating the material. Forexample, a portion of the conveyor can be sent through a heated zone.The heated zone can be created, for example, by IR radiation,microwaves, combustion (e.g., gas, coal, oil, biomass), resistiveheating and/or inductive coils. The heat can be applied from at leastone side or more than one side, can be continuous or periodic and can befor only a portion of the material or all the material. For example, aportion of the conveying trough can be heated by use of a heatingjacket. Heating can be, for example, for the purpose of drying thematerial. In the case of drying the material, this can also befacilitated, with or without heating, by the movement of a gas (e.g.,air, oxygen, nitrogen, He, CO₂, Argon) over and/or through the biomassas it is being conveyed.

Optionally, pre-treatment processing can include cooling the material.Cooling material is described in U.S. Pat. No. 7,900,857 to Medoff, thedisclosure of which in incorporated herein by reference. For example,cooling can be by supplying a cooling fluid, for example, water (e.g.,with glycerol), or nitrogen (e.g., liquid nitrogen) to the bottom of theconveying trough. Alternatively, a cooling gas, for example, chillednitrogen can be blown over the biomass materials or under the conveyingsystem.

Another optional pre-treatment processing method can include adding amaterial to the biomass. The additional material can be added by, forexample, by showering, sprinkling and or pouring the material onto thebiomass as it is conveyed. Materials that can be added include, forexample, metals, ceramics and/or ions as described in U.S. Pat. App.Pub. 2010/0105119 A1 (filed Oct. 26, 2009) and U.S. Pat. App. Pub.2010/0159569 A1 (filed Dec. 16, 2009), the entire disclosures of whichare incorporated herein by reference. Optional materials that can beadded include acids and bases. Other materials that can be added areoxidants (e.g., peroxides, chlorates), polymers, polymerizable monomers(e.g., containing unsaturated bonds), water, catalysts, enzymes and/ororganisms. Materials can be added, for example, in pure form, as asolution in a solvent (e.g., water or an organic solvent) and/or as asolution. In some cases the solvent is volatile and can be made toevaporate e.g., by heating and/or blowing gas as previously described.The added material may form a uniform coating on the biomass or be ahomogeneous mixture of different components (e.g., biomass andadditional material). The added material can modulate the subsequentirradiation step by increasing the efficiency of the irradiation,damping the irradiation or changing the effect of the irradiation (e.g.,from electron beams to X-rays or heat). The method may have no impact onthe irradiation but may be useful for further downstream processing. Theadded material may help in conveying the material, for example, bylowering dust levels.

Biomass can be delivered to the conveyor (e.g., the vibratory conveyorsused in the vaults herein described) by a belt conveyor, a pneumaticconveyor, a screw conveyor, a hopper, a pipe, manually or by acombination of these. The biomass can, for example, be dropped, pouredand/or placed onto the conveyor by any of these methods. In someembodiments the material is delivered to the conveyor using an enclosedmaterial distribution system to help maintain a low oxygen atmosphereand/or control dust and fines. Lofted or air suspended biomass fines anddust are undesirable because these can form an explosion hazard ordamage the window foils of an electron gun (if such a device is used fortreating the material).

The material can be leveled to form a uniform thickness between about0.0312 and 5 inches (e.g., between about 0.0625 and 2.000 inches,between about 0.125 and 1 inches, between about 0.125 and 0.5 inches,between about 0.3 and 0.9 inches, between about 0.2 and 0.5 inchesbetween about 0.25 and 1.0 inches, between about 0.25 and 0.5 inches,0.100+/−0.025 inches, 0.150+/−0.025 inches, 0.200+/−0.025 inches,0.250+/−0.025 inches, 0.300+/−0.025 inches, 0.350+/−0.025 inches,0.400+/−0.025 inches, 0.450+/−0.025 inches, 0.500+/−0.025 inches,0.550+/−0.025 inches, 0.600+/−0.025 inches, 0.700+/−0.025 inches,0.750+/−0.025 inches, 0.800+/−0.025 inches, 0.850+/−0.025 inches,0.900+/−0.025 inches, 0.900+/−0.025 inches.

Generally, it is preferred to convey the material as quickly as possiblethrough the electron beam to maximize throughput. For example, thematerial can be conveyed at rates of at least 1 ft./min, e.g., at least2 ft./min, at least 3 ft./min, at least 4 ft./min, at least 5 ft./min,at least 10 ft./min, at least 15 ft./min, 20, 25, 30, 35, 40, 45, 50ft./min. The rate of conveying is related to the beam current, forexample, for a ¼ inch thick biomass and 100 mA, the conveyor can move atabout 20 ft./min to provide a useful irradiation dosage, at 50 mA theconveyor can move at about 10 ft./min to provide approximately the sameirradiation dosage.

After the biomass material has been conveyed through the radiation zone,optional post-treatment processing can be done. The optionalpost-treatment processing can, for example, be a process described withrespect to the pre-irradiation processing. For example, the biomass canbe screened, heated, cooled, and/or combined with additives. Uniquely topost-irradiation, quenching of the radicals can occur, for example,quenching of radicals by the addition of fluids or gases (e.g., oxygen,nitrous oxide, ammonia, liquids), using pressure, heat, and/or theaddition of radical scavengers. For example, the biomass can be conveyedout of the enclosed conveyor and exposed to a gas (e.g., oxygen) whereit is quenched, forming carboxylated groups. In one embodiment, thebiomass is exposed during irradiation to the reactive gas or fluid.Quenching of biomass that has been irradiated is described in U.S. Pat.No. 8,083,906 to Medoff, the entire disclosure of which is incorporateherein by reference.

If desired, one or more mechanical treatments can be used in addition toirradiation to further reduce the recalcitrance of thecarbohydrate-containing material. These processes can be applied before,during and or after irradiation.

In some cases, the mechanical treatment may include an initialpreparation of the feedstock as received, e.g., size reduction ofmaterials, such as by comminution, e.g., cutting, grinding, shearing,pulverizing or chopping. For example, in some cases, loose feedstock(e.g., recycled paper, starchy materials, or switchgrass) is prepared byshearing or shredding. Mechanical treatment may reduce the bulk densityof the carbohydrate-containing material, increase the surface area ofthe carbohydrate-containing material and/or decrease one or moredimensions of the carbohydrate-containing material.

Alternatively, or in addition, the feedstock material can be treatedwith another treatment, for example, chemical treatments, such as withan acid (HCl, H₂SO₄, H₃PO₄), a base (e.g., KOH and NaOH), a chemicaloxidant (e.g., peroxides, chlorates, ozone), irradiation, steamexplosion, pyrolysis, sonication, oxidation, chemical treatment. Thetreatments can be in any order and in any sequence and combinations. Forexample, the feedstock material can first be physically treated by oneor more treatment methods, e.g., chemical treatment including and incombination with acid hydrolysis (e.g., utilizing HCl, H₂SO₄, H₃PO₄),radiation, sonication, oxidation, pyrolysis or steam explosion, and thenmechanically treated. This sequence can be advantageous since materialstreated by one or more of the other treatments, e.g., irradiation orpyrolysis, tend to be more brittle and, therefore, it may be easier tofurther change the structure of the material by mechanical treatment. Asanother example, a feedstock material can be conveyed through ionizingradiation using a conveyor as described herein and then mechanicallytreated. Chemical treatment can remove some or all of the lignin (forexample, chemical pulping) and can partially or completely hydrolyze thematerial. The methods also can be used with pre-hydrolyzed material. Themethods also can be used with material that has not been pre hydrolyzedThe methods can be used with mixtures of hydrolyzed and non-hydrolyzedmaterials, for example, with about 50% or more non-hydrolyzed material,with about 60% or more non-hydrolyzed material, with about 70% or morenon-hydrolyzed material, with about 80% or more non-hydrolyzed materialor even with 90% or more non-hydrolyzed material.

In addition to size reduction, which can be performed initially and/orlater in processing, mechanical treatment can also be advantageous for“opening up,” “stressing,” breaking or shattering thecarbohydrate-containing materials, making the cellulose of the materialsmore susceptible to chain scission and/or disruption of crystallinestructure during the physical treatment.

Methods of mechanically treating the carbohydrate-containing materialinclude, for example, milling or grinding Milling may be performedusing, for example, a hammer mill, ball mill, colloid mill, conical orcone mill, disk mill, edge mill, Wiley mill, grist mill or other mill.Grinding may be performed using, for example, a cutting/impact typegrinder. Some exemplary grinders include stone grinders, pin grinders,coffee grinders, and burr grinders. Grinding or milling may be provided,for example, by a reciprocating pin or other element, as is the case ina pin mill. Other mechanical treatment methods include mechanicalripping or tearing, other methods that apply pressure to the fibers, andair attrition milling Suitable mechanical treatments further include anyother technique that continues the disruption of the internal structureof the material that was initiated by the previous processing steps.

Mechanical feed preparation systems can be configured to produce streamswith specific characteristics such as, for example, specific maximumsizes, specific length-to-width, or specific surface areas ratios.Physical preparation can increase the rate of reactions, improve themovement of material on a conveyor, improve the irradiation profile ofthe material, improve the radiation uniformity of the material, orreduce the processing time required by opening up the materials andmaking them more accessible to processes and/or reagents, such asreagents in a solution.

The bulk density of feedstocks can be controlled (e.g., increased). Insome situations, it can be desirable to prepare a low bulk densitymaterial, e.g., by densifying the material (e.g., densification can makeit easier and less costly to transport to another site) and thenreverting the material to a lower bulk density state (e.g., aftertransport). The material can be densified, for example, from less thanabout 0.2 g/cc to more than about 0.9 g/cc (e.g., less than about 0.3 tomore than about 0.5 g/cc, less than about 0.3 to more than about 0.9g/cc, less than about 0.5 to more than about 0.9 g/cc, less than about0.3 to more than about 0.8 g/cc, less than about 0.2 to more than about0.5 g/cc). For example, the material can be densified by the methods andequipment disclosed in U.S. Pat. No. 7,932,065 to Medoff andInternational Publication No. WO 2008/073186 (which was filed Oct. 26,2007, was published in English, and which designated the United States),the full disclosures of which are incorporated herein by reference.Densified materials can be processed by any of the methods describedherein, or any material processed by any of the methods described hereincan be subsequently densified.

In some embodiments, the material to be processed is in the form of afibrous material that includes fibers provided by shearing a fibersource. For example, the shearing can be performed with a rotary knifecutter.

For example, a fiber source, e.g., that is recalcitrant or that has hadits recalcitrance level reduced, can be sheared, e.g., in a rotary knifecutter, to provide a first fibrous material. The first fibrous materialis passed through a first screen, e.g., having an average opening sizeof 1.59 mm or less ( 1/16 inch, 0.0625 inch), provide a second fibrousmaterial. If desired, the fiber source can be cut prior to the shearing,e.g., with a shredder. For example, when a paper is used as the fibersource, the paper can be first cut into strips that are, e.g., ¼-to½-inch wide, using a shredder, e.g., a counter-rotating screw shredder,such as those manufactured by Munson (Utica, N.Y.). As an alternative toshredding, the paper can be reduced in size by cutting to a desired sizeusing a guillotine cutter. For example, the guillotine cutter can beused to cut the paper into sheets that are, e.g., 10 inches wide by 12inches long.

In some embodiments, the shearing of the fiber source and the passing ofthe resulting first fibrous material through a first screen areperformed concurrently. The shearing and the passing can also beperformed in a batch-type process.

For example, a rotary knife cutter can be used to concurrently shear thefiber source and screen the first fibrous material. A rotary knifecutter includes a hopper that can be loaded with a shredded fiber sourceprepared by shredding a fiber source.

In some implementations, the feedstock is physically treated prior tosaccharification and/or fermentation. Physical treatment processes caninclude one or more of any of those described herein, such as mechanicaltreatment, chemical treatment, irradiation, sonication, oxidation,pyrolysis or steam explosion. Treatment methods can be used incombinations of two, three, four, or even all of these technologies (inany order). When more than one treatment method is used, the methods canbe applied at the same time or at different times. Other processes thatchange a molecular structure of a biomass feedstock may also be used,alone or in combination with the processes disclosed herein.

Mechanical treatments that may be used, and the characteristics of themechanically treated carbohydrate-containing materials, are described infurther detail in U.S. Pat. App. Pub. 2012/0100577 A1, filed Oct. 18,2011, the full disclosure of which is hereby incorporated herein byreference.

The mechanical treatments described herein can also be applied toprocessing of PLA and PLA based materials.

Sonication, Pyrolysis, Oxidation, Steam Explosion

If desired, one or more sonication, pyrolysis, oxidative, or steamexplosion processes can be used instead of or in addition to irradiationto reduce or further reduce the recalcitrance of thecarbohydrate-containing material or process PLA and/or PLA basedmaterials. For example, these processes can be applied before, duringand or after irradiation. These processes are described in detail inU.S. Pat. No. 7,932,065 to Medoff, the full disclosure of which isincorporated herein by reference.

Heat Treatment of Biomass

Alternately, or in addition to the biomass may be heat treated for up totwelve hours at temperatures ranging from about 90° C. to about 160° C.Optionally, this heat treatment step is performed after biomass has beenirradiated with an electron beam. The amount of time for the heattreatment is up to 9 hours, alternately up to 6 hours, optionally up to4 hours and further up to about 2 hours. The treatment time can be up toas little as 30 minutes when the mass may be effectively heated.

The heat treatment can be performed 90° C. to about 160° C. or,optionally, at 100 to 150 or, alternatively, at 120 to 140° C. Thebiomass is suspended in water such that the biomass content is 10 to 75wt. % in water. In the case of the biomass being the irradiated biomasswater is added and the heat treatment performed.

The heat treatment is performed in an aqueous suspension or mixture ofthe biomass. The amount of biomass is 10 to 90 wt. % of the totalmixture, alternatively 20 to 70 wt. % or optionally 25 to 50 wt. %. Theirradiated biomass may have minimal water content so water must be addedprior to the heat treatment.

Since at temperatures above 100° C. there will be pressure vesselrequired to accommodate the pressure due to the vaporized of water. Theprocess for the heat treatment may be batch, continuous, semi-continuousor other reactor configurations. The continuous reactor configurationmay be a tubular reactor and may include device(s) within the tube whichwill facilitate heat transfer and mixing/suspension of the biomass.These tubular devices may include a one or more static mixers. The heatmay also be put into the system by direct injection of steam.

Use of Treated Biomass Material

Using the methods described herein, a starting biomass material (e.g.,plant biomass, animal biomass, paper, and municipal waste biomass) canbe used as feedstock to produce useful intermediates and products suchas organic acids, salts of organic acids, hydroxy-carboxylic acids, PLA,acid anhydrides, esters of organic acids and fuels, e.g., fuels forinternal combustion engines or feedstocks for fuel cells. Systems andprocesses are described herein that can use as feedstock cellulosicand/or lignocellulosic materials that are readily available, but oftencan be difficult to process, e.g., municipal waste streams and wastepaper streams, such as streams that include newspaper, kraft paper,corrugated paper or mixtures of these.

In order to convert the feedstock to a form that can be readilyprocessed, the glucan- or xylan-containing cellulose in the feedstockcan be hydrolyzed to low molecular weight carbohydrates, such as sugars,by a saccharifying agent, e.g., an enzyme or acid, a process referred toas saccharification. The low molecular weight carbohydrates can then beused, for example, in an existing manufacturing plant, such as a singlecell protein plant, an enzyme manufacturing plant, or a fuel plant,e.g., an ethanol manufacturing facility.

The feedstock can be hydrolyzed using an enzyme, e.g., by combining thematerials and the enzyme in a solvent, e.g., in an aqueous solution.

Alternatively, the enzymes can be supplied by organisms that break downbiomass, such as the cellulose and/or the lignin portions of thebiomass, contain or manufacture various cellulolytic enzymes(cellulases), ligninases or various small molecule biomass-degradingmetabolites. These enzymes may be a complex of enzymes that actsynergistically to degrade crystalline cellulose or the lignin portionsof biomass. Examples of cellulolytic enzymes include: endoglucanases,cellobiohydrolases, and cellobiases (beta-glucosidases).

During saccharification a cellulosic substrate can be initiallyhydrolyzed by endoglucanases at random locations producing oligomericintermediates. These intermediates are then substrates for exo-splittingglucanases such as cellobiohydrolase to produce cellobiose from the endsof the cellulose polymer. Cellobiose is a water-soluble 1,4-linked dimerof glucose. Finally, cellobiase cleaves cellobiose to yield glucose. Theefficiency (e.g., time to hydrolyze and/or completeness of hydrolysis)of this process depends on the recalcitrance of the cellulosic material.

Intermediates and Products

Using the processes described herein, the biomass material can beconverted to one or more products, such as energy, fuels, foods andmaterials. Specific examples of products include, but are not limitedto, hydrogen, sugars (e.g., glucose, xylose, arabinose, mannose,galactose, fructose, disaccharides, oligosaccharides andpolysaccharides), alcohols (e.g., monohydric alcohols or dihydricalcohols, such as ethanol, n-propanol, isobutanol, sec-butanol,tert-butanol or n-butanol), hydrated or hydrous alcohols (e.g.,containing greater than 10%, 20%, 30% or even greater than 40% water),biodiesel, organic acids, hydrocarbons (e.g., methane, ethane, propane,isobutene, pentane, n-hexane, biodiesel, bio-gasoline and mixturesthereof), co-products (e.g., proteins, such as cellulolytic proteins(enzymes) or single cell proteins), and mixtures of any of these in anycombination or relative concentration, and optionally in combinationwith any additives (e.g., fuel additives). Other examples includecarboxylic acids, salts of a carboxylic acid, a mixture of carboxylicacids and salts of carboxylic acids and esters of carboxylic acids(e.g., methyl, ethyl and n-propyl esters), ketones (e.g., acetone),aldehydes (e.g., acetaldehyde), alpha and beta unsaturated acids (e.g.,acrylic acid) and olefins (e.g., ethylene). Other alcohols and alcoholderivatives include propanol, propylene glycol, 1,4-butanediol,1,3-propanediol, sugar alcohols (e.g., erythritol, glycol, glycerol,sorbitol threitol, arabitol, ribitol, mannitol, dulcitol, fucitol,iditol, isomalt, maltitol, lactitol, xylitol and other polyols), andmethyl or ethyl esters of any of these alcohols. Other products includemethyl acrylate, methyl methacrylate, lactic acid, PLA, citric acid,formic acid, acetic acid, propionic acid, butyric acid, succinic acid,valeric acid, caproic acid, 3-hydroxypropionic acid, palmitic acid,stearic acid, oxalic acid, malonic acid, glutaric acid, oleic acid,linoleic acid, glycolic acid, gamma-hydroxybutyric acid, and mixturesthereof, salts of any of these acids, mixtures of any of the acids andtheir respective salts.

Any combination of the above products with each other, and/or of theabove products with other products, which other products may be made bythe processes described herein or otherwise, may be packaged togetherand sold as products. The products may be combined, e.g., mixed, blendedor co-dissolved, or may simply be packaged or sold together.

Any of the products or combinations of products described herein may besanitized or sterilized prior to selling the products, e.g., afterpurification or isolation or even after packaging, to neutralize one ormore potentially undesirable contaminants that could be present in theproduct(s). Such sanitation can be done with electron bombardment, forexample, be at a dosage of less than about 20 Mrad, e.g., from about 0.1to 15 Mrad, from about 0.5 to 7 Mrad, or from about 1 to 3 Mrad.

The processes described herein can produce various by-product streamsuseful for generating steam and electricity to be used in other parts ofthe plant (co-generation) or sold on the open market. For example, steamgenerated from burning by-product streams can be used in a distillationprocess. As another example, electricity generated from burningby-product streams can be used to power electron beam generators used inpretreatment.

The by-products used to generate steam and electricity are derived froma number of sources throughout the process. For example, anaerobicdigestion of wastewater can produce a biogas high in methane and a smallamount of waste biomass (sludge). As another example,post-saccharification and/or post-distillate solids (e.g., unconvertedlignin, cellulose, and hemicellulose remaining from the pretreatment andprimary processes) can be used, e.g., burned, as a fuel.

Other intermediates and products, including food and pharmaceuticalproducts, are described in U.S. Pat. App. Pub. 2010/0124583 A1,published May 20, 2010, to Medoff, the full disclosure of which ishereby incorporated by reference herein.

Lignin Derived Products

The spent biomass (e.g., spent lignocellulosic material) fromlignocellulosic processing by the methods described are expected to havea high lignin content and in addition to being useful for producingenergy through combustion in a Co-Generation plant, may have uses asother valuable products. For example, the lignin can be used as capturedas a plastic, or it can be synthetically upgraded to other plastics. Insome instances, it can also be converted to lignosulfonates, which canbe utilized as binders, dispersants, emulsifiers or as sequestrants.

When used as a binder, the lignin or a lignosulfonate can, e.g., beutilized in coal briquettes, in ceramics, for binding carbon black, forbinding fertilizers and herbicides, as a dust suppressant, in the makingof plywood and particle board, for binding animal feeds, as a binder forfiberglass, as a binder in linoleum paste and as a soil stabilizer.

As a dispersant, the lignin or lignosulfonates can be used, e.g.,concrete mixes, clay and ceramics, dyes and pigments, leather tanningand in gypsum board.

As an emulsifier, the lignin or lignosulfonates can be used, e.g., inasphalt, pigments and dyes, pesticides and wax emulsions.

As a sequestrant, the lignin or lignosulfonates can be used, e.g., inmicro-nutrient systems, cleaning compounds and water treatment systems,e.g., for boiler and cooling systems.

For energy production lignin generally has a higher energy content thanholocellulose (cellulose and hemicellulose) since it contains morecarbon than holocellulose. For example, dry lignin can have an energycontent of between about 11,000 and 12,500 BTU per pound, compared to7,000 an 8,000 BTU per pound of holocellulose. As such, lignin can bedensified and converted into briquettes and pellets for burning. Forexample, the lignin can be converted into pellets by any methoddescribed herein. For a slower burning pellet or briquette, the lignincan be crosslinked, such as applying a radiation dose of between about0.5 Mrad and 5 Mrad. Crosslinking can make a slower burning form factor.The form factor, such as a pellet or briquette, can be converted to a“synthetic coal” or charcoal by pyrolyzing in the absence of air, e.g.,at between 400 and 950° C. Prior to pyrolyzing, it can be desirable tocrosslink the lignin to maintain structural integrity.

Co-generation using spent biomass is described in International App. No.PCT/US2014/021634 filed Mar. 7, 2014, the entire disclosure therein isherein incorporated by reference.

Lignin derived products can also be combined with PLA and PLA derivedproducts. (e.g., PLA that has been produced as described herein). Forexample, lignin and lignin derived products can be blended, grafted toor otherwise combined and/or mixed with PLA. The lignin can, forexample, be useful for strengthening, plasticizing or otherwisemodifying the PLA.

Saccharification

The treated biomass materials can be saccharified, generally bycombining the material and a cellulase enzyme in a fluid medium, e.g.,an aqueous solution. In some cases, the material is boiled, steeped, orcooked in hot water prior to saccharification, as described in U.S. Pat.App. Pub. 2012/0100577 A1 by Medoff and Masterman, published on Apr. 26,2012, the entire contents of which are incorporated herein.

The saccharification may be done by inoculating a raw sugar mixtureproduced by saccharifying a reduced recalcitrance lignocellulosicmaterial to produce a hydroxy-carboxylic acid. The hydroxy-carboxylicacid can be selected from the group glycolic acid, D-lactic acid,L-lactic acid, D-malic acid, L-malic, citric acid and D-tartaric acid,L-tartaric acid, and meso-tartaric acid. The raw sugar mixture can bethe reduced recalcitrance lignocellulosic material which was processedby irradiating the lignocellulosic material with an electron beam.

The saccharification process can be partially or completely performed ina tank (e.g., a tank having a volume of at least 4000, 40,000, or500,000 L) in a manufacturing plant, and/or can be partially orcompletely performed in transit, e.g., in a rail car, tanker truck, orin a supertanker or the hold of a ship. The time required for completesaccharification will depend on the process conditions and thecarbohydrate-containing material and enzyme used. If saccharification isperformed in a manufacturing plant under controlled conditions, thecellulose may be substantially entirely converted to sugar, e.g.,glucose in about 12-96 hours. If saccharification is performed partiallyor completely in transit, saccharification may take longer.

It is generally preferred that the tank contents be mixed duringsaccharification, e.g., using jet mixing as described in InternationalApp. No. PCT/US2010/035331, filed May 18, 2010, which was published inEnglish as WO 2010/135380 and designated the United States, the fulldisclosure of which is incorporated by reference herein.

The addition of surfactants can enhance the rate of saccharification.Examples of surfactants include non-ionic surfactants, such as a Tween®20 or Tween® 80 polyethylene glycol surfactants, ionic surfactants, oramphoteric surfactants.

It is generally preferred that the concentration of the sugar solutionresulting from saccharification be relatively high, e.g., greater than40%, or greater than 50, 60, 70, 80, 90 or even greater than 95% byweight. Water may be removed, e.g., by evaporation, to increase theconcentration of the sugar solution. This reduces the volume to beshipped, and also inhibits microbial growth in the solution.

Alternatively, sugar solutions of lower concentrations may be used, inwhich case it may be desirable to add an antimicrobial additive, e.g., abroad spectrum antibiotic, in a low concentration, e.g., 50 to 150 ppm.Other suitable antibiotics include amphotericin B, ampicillin,chloramphenicol, ciprofloxacin, gentamicin, hygromycin B, kanamycin,neomycin, penicillin, puromycin, streptomycin. Antibiotics will inhibitgrowth of microorganisms during transport and storage, and can be usedat appropriate concentrations, e.g., between 15 and 1000 ppm by weight,e.g., between 25 and 500 ppm, or between 50 and 150 ppm. If desired, anantibiotic can be included even if the sugar concentration is relativelyhigh. Alternatively, other additives with anti-microbial of preservativeproperties may be used. Preferably the antimicrobial additive(s) arefood-grade.

A relatively high concentration solution can be obtained by limiting theamount of water added to the carbohydrate-containing material with theenzyme. The concentration can be controlled, e.g., by controlling howmuch saccharification takes place. For example, concentration can beincreased by adding more carbohydrate-containing material to thesolution. In order to keep the sugar that is being produced in solution,a surfactant can be added, e.g., one of those discussed above.Solubility can also be increased by increasing the temperature of thesolution. For example, the solution can be maintained at a temperatureof 40-50° C., 60-80° C., or even higher.

Saccharifying Agents

Suitable cellulolytic enzymes include cellulases from species in thegenera Bacillus, Coprinus, Myceliophthora, Cephalosporium, Scytalidium,Penicillium, Aspergillus, Pseudomonas, Humicola, Fusarium, Thielavia,Acremonium, Chrysosporium and Trichoderma, especially those produced bya strain selected from the species Aspergillus (see, e.g., EP Pub. No. 0458 162), Humicola insolens (reclassified as Scytalidium thermophilum,see, e.g., U.S. Pat. No. 4,435,307), Coprinus cinereus, Fusariumoxysporum, Myceliophthora thermophila, Meripilus giganteus, Thielaviaterrestris, Acremonium sp. (including, but not limited to, A.persicinum, A. acremonium, A. brachypenium, A. dichromosporum, A.obclavatum, A. pinkertoniae, A. roseogriseum, A. incoloratum, and A.furatum). Preferred strains include Humicola insolens DSM 1800, Fusariumoxysporum DSM 2672, Myceliophthora thermophila CBS 117.65,Cephalosporium sp. RYM-202, Acremonium sp. CBS 478.94, Acremonium sp.CBS 265.95, Acremonium persicinum CBS 169.65, Acremonium acremonium AHU9519, Cephalosporium sp. CBS 535.71, Acremonium brachypenium CBS 866.73,Acremonium dichromosporum CBS 683.73, Acremonium obclavatum CBS 311.74,Acremonium pinkertoniae CBS 157.70, Acremonium roseogriseum CBS 134.56,Acremonium incoloratum CBS 146.62, and Acremonium furatum CBS 299.70H.Cellulolytic enzymes may also be obtained from Chrysosporium, preferablya strain of Chrysosporium lucknowense. Additional strains that can beused include, but are not limited to, Trichoderma (particularly T.viride, T. reesei, and T. koningii), alkalophilic Bacillus (see, forexample, U.S. Pat. No. 3,844,890 and EP Pub. No. 0 458 162), andStreptomyces (see, e.g., EP Pub. No. 0 458 162).

In addition to or in combination to enzymes, acids, bases and otherchemicals (e.g., oxidants) can be utilized to saccharify lignocellulosicand cellulosic materials. These can be used in any combination orsequence (e.g., before, after and/or during addition of an enzyme). Forexample, strong mineral acids can be utilized (e.g. HCl, H₂SO₄, H₃PO₄)and strong bases (e.g., NaOH, KOH).

Sugars

In the processes described herein, for example, after saccharification,sugars (e.g., glucose and xylose) can be isolated. For example, sugarscan be isolated by precipitation, crystallization, chromatography (e.g.,simulated moving bed chromatography, high pressure chromatography),centrifugation, extraction, any other isolation method known in the art,and combinations thereof.

Hydrogenation and Other Chemical Transformations

The processes described herein can include hydrogenation. For example,glucose and xylose can be hydrogenated to sorbitol and xylitolrespectively. Esters, for example, produced as described herein, canalso be hydrogenated. Hydrogenation can be accomplished by use of acatalyst (e.g., Pt/gamma-Al₂O₃, Ru/C, Raney Nickel, copper chromite orother catalysts know in the art) in combination with H₂ under highpressure (e.g., 10 to 12000 psi). Other types of chemical transformationof the products from the processes described herein can be used, forexample, production of organic sugar derived products such (e.g.,furfural and furfural-derived products). Chemical transformations ofsugar derived products are described in International App. No.PCT/US201/049562, filed Jul. 3, 2013, the disclosure of which isincorporated herein by reference in its entirety.

Fermentation

Yeast and Zymomonas bacteria, for example, can be used for fermentationor conversion of sugar(s) to alcohol(s). Other microorganisms arediscussed below. The optimum pH for fermentations is about pH 4 to 7.For example, the optimum pH for yeast is from about pH 4 to 5, while theoptimum pH for Zymomonas is from about pH 5 to 6. Typical fermentationtimes are about 24 to 168 hours (e.g., 24 to 96 hrs.) with temperaturesin the range of 20° C. to 40° C. (e.g., 26° C. to 40° C.), howeverthermophilic microorganisms prefer higher temperatures.

In some embodiments, e.g., when anaerobic organisms are used, at least aportion of the fermentation is conducted in the absence of oxygen, e.g.,under a blanket of an inert gas such as N₂, Ar, He, CO₂ or mixturesthereof. Additionally, the mixture may have a constant purge of an inertgas flowing through the tank during part of or all of the fermentation.In some cases, anaerobic condition, can be achieved or maintained bycarbon dioxide production during the fermentation and no additionalinert gas is needed.

In some embodiments, all or a portion of the fermentation process can beinterrupted before the low molecular weight sugar is completelyconverted to a product (e.g., ethanol). The intermediate fermentationproducts include sugar and carbohydrates in high concentrations. Thesugars and carbohydrates can be isolated via any means known in the art.These intermediate fermentation products can be used in preparation offood for human or animal consumption. Additionally or alternatively, theintermediate fermentation products can be ground to a fine particle sizein a stainless-steel laboratory mill to produce a flour-like substance.Jet mixing may be used during fermentation, and in some casessaccharification and fermentation are performed in the same tank.

Nutrients for the microorganisms may be added during saccharificationand/or fermentation, for example, the food-based nutrient packagesdescribed in U.S. Pat. App. Pub. 2012/0052536, filed Jul. 15, 2011, thecomplete disclosure of which is incorporated herein by reference.

“Fermentation” includes the methods and products that are disclosed inInternational App. No. PCT/US2012/071093 filed Dec. 20, 2012 andInternational App. No. PCT/US2012/071097 filed Dec. 12, 2012, thecontents of both of which are incorporated by reference herein in theirentirety.

Mobile fermenters can be utilized, as described in International App.No. PCT/US2007/074028 (which was filed Jul. 20, 2007, was published inEnglish as WO 2008/011598 and designated the United States) and has a USissued U.S. Pat. No. 8,318,453, the contents of which are incorporatedherein in its entirety. Similarly, the saccharification equipment can bemobile. Further, saccharification and/or fermentation may be performedin part or entirely during transit.

Fermentation Agents

The microorganism(s) used in fermentation can be naturally-occurringmicroorganisms and/or engineered microorganisms. For example, themicroorganism can be a bacterium (including, but not limited to, e.g., acellulolytic bacterium), a fungus, (including, but not limited to, e.g.,a yeast), a plant, a protist, e.g., a protozoa or a fungus-like protest(including, but not limited to, e.g., a slime mold), or an alga. Whenthe organisms are compatible, mixtures of organisms can be utilized.

Suitable fermenting microorganisms have the ability to convertcarbohydrates, such as glucose, fructose, xylose, arabinose, mannose,galactose, oligosaccharides or polysaccharides into fermentationproducts. Fermenting microorganisms include strains of the genusSaccharomyces spp. (including, but not limited to, S. cerevisiae(baker's yeast), S. distaticus, S. uvarum), the genus Kluyveromyces,(including, but not limited to, K. marxianus, K. fragilis), the genusCandida (including, but not limited to, C. pseudotropicalis, and C.brassicae), Pichia stipitis (a relative of Candida shehatae), the genusClavispora (including, but not limited to, C. lusitaniae and C.opuntiae), the genus Pachysolen (including, but not limited to, P.tannophilus), the genus Bretannomyces (including, but not limited to,e.g., B. clausenii (Philippidis, G. P., 1996, Cellulose bioconversiontechnology, in Handbook on Bioethanol: Production and Utilization,Wyman, C. E., ed., Taylor & Francis, Washington, DC, 179-212)). Othersuitable microorganisms include, for example, Zymomonas mobilis,Clostridium spp. (including, but not limited to, C. thermocellum(Philippidis, 1996, supra), C. saccharobutylacetonicum, C. tyrobutyricumC. saccharobutylicum, C. Puniceum, C. beijemckii, and C.acetobutylicum), Moniliella spp. (including but not limited to M.pollinis, M. tomentosa, M. madida, M. nigrescens, M. oedocephali, M.megachiliensis), Yarrowia lipolytica, Aureobasidium sp.,Trichosporonoides sp., Trigonopsis variabilis, Trichosporon sp.,Moniliellaacetoabutans sp., Typhula variabilis, Candida magnoliae,Ustilaginomycetes sp., Pseudozyma tsukubaensis, yeast species of generaZygosaccharomyces, Debaryomyces, Hansenula and Pichia, and fungi of thedematioid genus Torula (e.g., T. corallina).

Many such microbial strains are publicly available, either commerciallyor through depositories such as the ATCC (American Type CultureCollection, Manassas, Va., USA), the NRRL (Agricultural Research ServiceCulture Collection, Peoria, Ill., USA), or the DSMZ (Deutsche Sammlungvon Mikroorganismen and Zellkulturen GmbH, Braunschweig, Germany), toname a few.

Commercially available yeasts include, for example, Red Star®/LesaffreEthanol Red (available from Red Star/Lesaffre, USA), FALI® (availablefrom Fleischmann's Yeast, a division of Burns Philip Food Inc., USA),SUPERSTART® (available from Alltech, now Lallemand), GERT STRAND®(available from Gert Strand AB, Sweden) and FERMOL® (available from DSMSpecialties).

Distillation

After fermentation, the resulting fluids can be distilled using, forexample, a “beer column” to separate ethanol and other alcohols from themajority of water and residual solids. The vapor exiting the beer columncan be, e.g., 35% by weight ethanol and can be fed to a rectificationcolumn. A mixture of nearly azeotropic (92.5%) ethanol and water fromthe rectification column can be purified to pure (99.5%) ethanol usingvapor-phase molecular sieves. The beer column bottoms can be sent to thefirst effect of a three-effect evaporator. The rectification columnreflux condenser can provide heat for this first effect. After the firsteffect, solids can be separated using a centrifuge and dried in a rotarydryer. A portion (25%) of the centrifuge effluent can be recycled tofermentation and the rest sent to the second and third evaporatoreffects. Most of the evaporator condensate can be returned to theprocess as fairly clean condensate with a small portion split off towaste water treatment to prevent build-up of low-boiling compounds.

Hydrocarbon-Containing Materials

In other embodiments utilizing the methods and systems described herein,hydrocarbon-containing materials can be processed. Any process describedherein can be used to treat any hydrocarbon-containing material hereindescribed. “Hydrocarbon-containing materials,” as used herein, is meantto include oil sands, oil shale, tar sands, coal dust, coal slurry,bitumen, various types of coal, and other naturally-occurring andsynthetic materials that include both hydrocarbon components and solidmatter. The solid matter can include rock, sand, clay, stone, silt,drilling slurry, or other solid organic and/or inorganic matter. Theterm can also include waste products such as drilling waste andby-products, refining waste and by-products, or other waste productscontaining hydrocarbon components, such as asphalt shingling andcovering, asphalt pavement, etc.

Conveying Systems

Various conveying systems can be used to convey the feedstock materials,for example, to a vault and under an electron beam in a vault. Exemplaryconveyors are belt conveyors, pneumatic conveyors, screw conveyors,carts, trains, trains or carts on rails, elevators, front loaders,backhoes, cranes, various scrapers and shovels, trucks, and throwingdevices can be used. For example, vibratory conveyors can be used invarious processes described herein, for example, as disclosed inInternational App. No. PCT/US2013/064332 filed Oct. 10, 2013, the entiredisclosure of which is herein incorporated by reference.

Other Embodiments

Any material, processes or processed materials described herein can beused to make products and/or intermediates such as composites, fillers,binders, plastic additives, adsorbents and controlled release agents.The methods can include densification, for example, by applying pressureand heat to the materials. For example, composites can be made bycombining fibrous materials with a resin or polymer (e.g., PLA). Forexample, radiation cross-linkable resin (e.g., a thermoplastic resin,PLA, and/or PLA derivatives) can be combined with a fibrous material toprovide a fibrous material/cross-linkable resin combination. Suchmaterials can be, for example, useful as building materials, protectivesheets, containers and other structural materials (e.g., molded and/orextruded products). Absorbents can be, for example, in the form ofpellets, chips, fibers and/or sheets. Adsorbents can be used, forexample, as pet bedding, packaging material or in pollution controlsystems. Controlled release matrices can also be the form of, forexample, pellets, chips, fibers and or sheets. The controlled releasematrices can, for example, be used to release drugs, biocides,fragrances. For example, composites, absorbents and control releaseagents and their uses are described in International Application No.PCT/US2006/010648, filed Mar. 23, 2006, and U.S. Pat. No. 8,074,910filed Nov. 22, 2011, the entire disclosures of which are hereinincorporated by reference.

In some instances the biomass material is treated at a first level toreduce recalcitrance, e.g., utilizing accelerated electrons, toselectively release one or more sugars (e.g., xylose). The biomass canthen be treated to a second level to release one or more other sugars(e.g., glucose). Optionally the biomass can be dried between treatments.The treatments can include applying chemical and biochemical treatmentsto release the sugars. For example, a biomass material can be treated toa level of less than about 20 Mrad (e.g., less than about 15 Mrad, lessthan about 10 Mrad, less than about 5 Mrad, less than about 2 Mrad) andthen treated with a solution of sulfuric acid, containing less than 10%sulfuric acid (e.g., less than about 9%, less than about 8%, less thanabout 7%, less than about 6%, less than about 5%, less than about 4%,less than about 3%, less than about 2%, less than about 1%, less thanabout 0.75%, less than about 0.50%, less than about 0.25%) to releasexylose. Xylose, for example, that is released into solution, can beseparated from solids and optionally the solids washed with asolvent/solution (e.g., with water and/or acidified water). Optionally,the Solids can be dried, for example, in air and/or under vacuumoptionally with heating (e.g., below about 150° C., below about 120° C.)to a water content below about 25 wt. % (below about 20 wt. %, belowabout 15 wt. %, below about 10 wt. %, below about 5 wt. %). The solidscan then be treated with a level of less than about 30 Mrad (e.g., lessthan about 25 Mrad, less than about 20 Mrad, less than about 15 Mrad,less than about 10 Mrad, less than about 5 Mrad, less than about 1 Mrador even not at all) and then treated with an enzyme (e.g., a cellulase)to release glucose. The glucose (e.g., glucose in solution) can beseparated from the remaining solids. The solids can then be furtherprocessed, for example, utilized to make energy or other products (e.g.,lignin derived products).

EXAMPLES L-Lactic Acid Production from Saccharified Corncob inLactobacillus Species Material and Methods Lactic Acid Producing StrainsTested:

The Lactic acid producing stains that were tested are listed in Table 2

TABLE 2 Lactic acid producing strains tested NRRL B-441 Lactobacilluscasei NRRL B-445 Lactobacillus rhamnosus NRRL B-763 Lactobacillusdelbrueckii subspecies delbrueckii ATCC 8014 Lactobacillus plantarumATCC 9649 Lactobacillus delbrueckii subspecies delbrueckii B-4525Lactobacillus delbrueckii subspecies lactis B-4390 Lactobacilluscoryniformis subspecies torquens B-227 Lactobacillus pentosus B-4527Lactobacillus brevis ATCC 25745 Pediococcus pentosaceus NRRL 395Rhizopus oryzae CBS 112.07 Rhizopus oryzae CBS 127.08 Rhizopus oryzaeCBS 396.95 Rhizopus oryzae

Seed Culture

Cells from a frozen (−80° C.) cell bank were cultivated in propagationmedium (BD DIFCO™ Lactobacilli MRS Broth) at 37° C., with 150 rpmstirring for 20 hours. This seed culture was transferred to a 1.2 L (oroptionally a 20 L) bioreactors charged with media as describe below.

Main Culture Media

All media included saccharified corncob that had been hammer milled andirradiated with about 35 Mrad of electron beam irradiation. For example,saccharified corn cob can be prepared as described in International App.No. PCT/US2014/021796 filed Mar. 7, 2014, the entire disclosure of whichis herein incorporated by reference.

Experiments with various additional media components were also conductedusing Lactobacillus casei NRRL B-44 as the lactic acid producingorganism. A 1.2 L bioreactor with 0.7 L of culture volume was used. A 1%of 20-hour-cultured seed of Lactobacillus casei NRRL B-441 wasinoculated. No aeration was utilized. The temperature was maintained atabout 37° C. Antifoam 204 was also added (0.1%, 1 ml/L) at the beginningof the fermentation.

The experiments are summarized in Table 3. The media components; initialglucose concentration, nitrogen sources, yeast extract concentration,calcium carbonate, metals and inoculum size, were tested for lactic acidyield or lactic acid production rate. In addition to media components,the physical conditions; temperature, agitation, autoclave time andheating (no-autoclave) were tested for lactic acid yield. For thesemedia components and physical reaction conditions the ranges tested,ranges for producing some lactic acid and the ranges are indicated inTable 3.

TABLE 3 L-Lactic acid production in bioreactor with B-441 Media TestComponent Parameter Range-Tested Range^(a) Range-Optional^(b) Initialglucose Lactic acid 33-85 g/L  33-75 g/L 33-52 g/L concentrationconcentration Nitrogen Lactic acid Yeast extract, Yeast extract, Yeastextract Sources Tested concentration Malt extract, Tryptone, Corn steep,Peptone Tryptone, Peptone Yeast Extract ^(c) Lactic acid  0-10 g/L2.5-10 g/L    2.5 g/L concentration Calcium Lactic acid 0-7 wt. %/vol. %3-7% wt. %/vol. % 5 wt. %/vol. % carbonate concentration Metal SolutionsLactic acid With or without With or Without metals concentration metalswithout metals Minor Lactic acid With or without With or Without minorcomponents: concentration minor without minor components sodium acetatecomponents components Polysorbate ™ 80^(d), dipotassium hydrogenphosphate, triammonium citrate Inoculum Size Lactic acid 0.1-5 vol. %1-5 vol. % 1 vol. % production rate Physical Test Condition ParameterRange-Tested Range- Range Temperature Lactic acid 27-47° C. 27-42° C.33-37° C. concentration Agitation (in Lactic acid 50-400 rpm 50-400 rpm100-300 rpm 1.2L reactor) concentration Autoclave Time Lactic acid 25min-145 min 25 min-145 min 25 min concentration Heating (no Lactic acid50-70° C. 50-70° C. 50-70° C. autoclave) concentration ^(a)Rangesproduced a yield of at least 80% based on added sugars. ^(b)Optionalranges produced close to 100% lactic acid (e.g., between about 90 and100%, between about 95 and 100%) ^(c) Fluka brand yeast extract wasused. ^(d)Polysorbate ™80 is a nonionic surfactant from ICI Americas,Inc.Results with Optional Media and Optional Physical Conditions

A 1.2 L bioreactor charged with 0.7 L of media (Saccharified corncob,2.5 g/L yeast extract). The media and bioreactor vessel were autoclavedfor 25 min and no additional heating was used for sterilization. Inaddition a 20 L bioreactor was charged with 10 L of media. Forsterilization the media was stirred at 200 rpm while heating at 80° C.for 10 min. When the media was cool (about 37° C.) the bioreactors wereinoculated with 1 vol. % of 20-hour-culture. The fermentations wereconducted under the physical conditions (37° C., 200 rpm stirring). Noaeration was utilized. The pH remained between 5 and 6 using 5% (wt.%/vol. %) throughout the fermentation. The temperature was maintained atabout 37° C. Antifoam 204 was also added (0.1vol. %) at the beginning ofthe fermentation. Several Lactobacillus casei strains were tested (NRRLB-441, NRRL B-445, NRRL B-763 and ATCC 8014).

A plot of the sugar consumption and lactic acid production for the NRRLB-441 strain is shown in the 1.2 L bioreactor is shown in FIG. 7. Aftertwo days all of the glucose was consumed, while xylose was not consumed.Fructose and cellobiose were also consumed. Lactic acid was produced ata concentration of about 42 g/L. The consumed glucose, fructose andcellobiose (total 42 g/L) were about to same as produced lactic acid.

Similar data from results of the fermentation using the NRRL B-441strain in the 20 L bioreactor are shown in FIG. 8. Glucose wascompletely consumed while xylose was not significantly consumed. Lacticacid was produced at a final concentration of about 47-48 g/L.

Enantiomer analysis is summarized for all strains tested in Table 4.Lactobacillus casei (NRRL-B-441) and L. rhamnosus (B-445) produced morethan 96% L-lactic acid. L. delbrueckii sub. Delbrueckii (B-763) showedover 99% of the D-Lactic acid. The L. plantarum (ATCC 8014) showed anapproximate equal mixture of each enantiomer.

TABLE 4 Ratio of L and D-Lactic Acid for Various Fermenting OrganismsStrain L-Lactic Acid D-Lactic Acid L. casei (B-441) 96.1 3.9 L.rhamnosus (B-445) 98.3 1.7 L. delbrueckii sub. 0.6 99.4 Delbrueckii(B-763) L. plantarum (ATCC 8014) 52.8 47.2

Polymerization of Lactic Acid

A 250 ml three-necked flask was equipped with a mechanical stirrer and acondenser that was connected with a vacuum system through a cold trap.100 grams of 90 wt. % aqueous L-lactic acid was dehydrated at 150° C.,first at atmospheric pressure for 2 hours, then at a reduced pressure of90 mmHg for 2 hours, and finally under a pressure of 20 mmHg for another4 hours. A clear viscous liquid of oligo(L-lactic acid) was formedquantitatively.

400 mg (0.4 wt. %) of both tin(II) chloride dihydrate and para-toluenesulfonic acid was acid was added to the mixture and further heated to180° C. for 5 hours at 8 mmHg With the reaction proceeding, the systembecame more viscous gradually. The reaction mixture was cooled down andthen further heated at 150° C. in a vacuum oven another 19 hours.

Samples were taken from the reaction mixture after 2 hours (A), 5 hours(B) and 24 hours (C) and the molecular weight was calculated using GPCusing polystyrene standards in THF. FIG. 9 is a plot of GPC data forsamples A, B and C.

Reaction time Molecular Retention Sample (hours) Weight Time A  2  800018.3 B  5 12000 19.3 C 24 35000 20.3

Other than in the examples herein, or unless otherwise expresslyspecified, all of the numerical ranges, amounts, values and percentages,such as those for amounts of materials, elemental contents, times andtemperatures of reaction, ratios of amounts, and others, in thefollowing portion of the specification and attached claims may be readas if prefaced by the word “about” even though the term “about” may notexpressly appear with the value, amount, or range. Accordingly, unlessindicated to the contrary, the numerical parameters set forth in thefollowing specification and attached claims are approximations that mayvary depending upon the desired properties sought to be obtained by thepresent invention. At the very least, and not as an attempt to limit theapplication of the doctrine of equivalents to the scope of the claims,each numerical parameter should at least be construed in light of thenumber of reported significant digits and by applying ordinary roundingtechniques.

Notwithstanding that the numerical ranges and parameters setting forththe broad scope of the invention are approximations, the numericalvalues set forth in the specific examples are reported as precisely aspossible. Any numerical value, however, inherently contains errornecessarily resulting from the standard deviation found in itsunderlying respective testing measurements. Furthermore, when numericalranges are set forth herein, these ranges are inclusive of the recitedrange end points (i.e., end points may be used). When percentages byweight are used herein, the numerical values reported are relative tothe total weight.

Also, it should be understood that any numerical range recited herein isintended to include all sub-ranges subsumed therein. For example, arange of “1 to 10” is intended to include all sub-ranges between (andincluding) the recited minimum value of 1 and the recited maximum valueof 10, that is, having a minimum value equal to or greater than 1 and amaximum value of equal to or less than 10. The terms “one,” “a,” or “an”as used herein are intended to include “at least one” or “one or more,”unless otherwise indicated.

Any patent, publication, or other disclosure material, in whole or inpart, that is said to be incorporated by reference herein isincorporated herein only to the extent that the incorporated materialdoes not conflict with existing definitions, statements, or otherdisclosure material set forth in this disclosure. As such, and to theextent necessary, the disclosure as explicitly set forth hereinsupersedes any conflicting material incorporated herein by reference.Any material, or portion thereof, that is said to be incorporated byreference herein, but which conflicts with existing definitions,statements, or other disclosure material set forth herein will only beincorporated to the extent that no conflict arises between thatincorporated material and the existing disclosure material.

While this invention has been particularly shown and described withreferences to most preferred embodiments thereof, it will be understoodby those skilled in the art that various changes in form and details maybe made therein without departing from the scope of the inventionencompassed by the appended claims.

What is claimed:
 1. A method for making a product comprising: treating areduced recalcitrance lignocellulosic or cellulosic material with one ormore enzymes and/or organisms to produce an alpha, beta, gamma and/ordelta hydroxy-carboxylic acid, and converting the alpha, beta, gammaand/or delta hydroxy-carboxylic acid to the product.